a, ees “GEOLOGICAL MAGAZINE: Monthly Journal of Geologn: WITH WHICH I8 INCORPORATED MP IBID Er DO ALKOKE mI CS 105% NOS. CCLKX XXIII. TO CCXCIV. EDITED BY HENRY WOODWARD, LL.D., F.R.S., V.P.G.S., F.Z.8., F.R.MS., OF THE BRITISH MUSEUM OF NATURAL HISTORY; VICE-PRESIDENT OF THE PALZONTOGRAPHICAL SOCIETY, MEMBER OF THE LYCEUM OF NATURAL HISTORY, NEW YORK; AND OF THE AMERICAN PHILOSOPHIOAL SOCIETY, PHILADELPHIA; HONORARY MEMBER OF THE YORKSHIRE PHILOSOPHICAL SOCIETY; OF THE GEOLOGISTS’ ASSOCIATION, LONDON; OF THE GEOLOGICAL SOCIETIES OF EDINBURGH, GLASGOW, HALIFAX, LIVERPOOL, AND NOER- WICH; CORRESPONDING MEMBER OF THE GEOLOGICAL SOCEETY OF BELGIUM; OF THE IMPERIAL SOCIETY OF NATURAL HISTORY OF MOSCOW; OF THE NATURAL HISTORY SOCIETY OF MONTREAL; AND OF THE MALACOLOGICAL SOCIETY OF BELGIUM. ASSISTED BY ROBERT ETHERIDGE, F.BS. L. & E., F.GS., F.CS., &., OF THE BRITISH MUSEUM OF NATURAL HISTORY. WILFRID H. HUDLESTON, M.A., F.R.S., Sec.G.8. AND GEORGE J. HINDE, Px.D., F.G.S., &. NEW SERIES. DECADE III. VOL. V. JANUARY—DECEMBER, 1888. TORN DI OUNF TRUBNER & Co, 57 anv 59, LUDG&ADE HILL, > F. SAVY, 77, BOULEVART ST.-GERY 1888. IN) ‘PARIS. 13 Ob © HERTFORD: PRINTED BY STEPHEN AUSTIN AND SONS. THE GEOLOGICAL MAGAZINE. DECADE III. VOL. V. JANUARY—DECEMBER 1888. ails LIST OF WOODCUTS. Gular plate of Stegosaurus ungulatus, Marsh « «+ + + + «© © Caudal plate of ae a Dorsal plate of x5 $6 55 evs). set cop reR Me Fs Mitcheldeania gregaria, Nich. eile We). be) ANeV niet eet Vive 2 5 06 AMOTL co nome Mirai. "6 Suc © Solenopora compacta, Billings LO LOM Od SEO aSrOr oO Oe o Solenopora ? filiformis, Nich, .»« + «© «© «© © «© © «© «© « Girvanella problematica, Nich. and Eth. jun. st] hive RU sneonadts JEG (CUPOIT ISG, IDENYSION 6) a0) GG oO G6 by 6 Vo! Vo Six Sections of Favositoid Corals . . © »% «© « «© «= - rismMofaGlancoplane: sty sey troll on lie) Wiel ite!” lis) Leth Mrepalplento) lie feet hyo Ehyllopod) Crustaceans (5) yal) il be) e)) | 0) ior eliniey |) —__ T.—Tue Natura History or Lavas as ILLUSTRATED BY THE MaTERIALS EJECTED FROM KRAKATOA.! By Prof. Joun W. Jupp, F.R.S., Pres.G.S. HORTLY after the great volcanic eruption at Krakatoa, in August, 1885, the Royal Society appointed a Committee to collect and sift the records of that remarkable outbreak and to study the effects which appear to have resulted from it. The investigation of the voleanic phenomena and of the materials ejected from the volcano having been committed to me, I have been led to some conclusions of considerable geological interest, the full discussion of which could scarcely find a place in the report which has been pub- lished by the Committee. It is these general results which I propose to discuss in the following communication. For the opportunity of studying the different rocks of Krakatoa, I am indebted to many correspondents who have supplied me with the necessary materials, and especially to M. René Bréon, who visited the volcano shortly after the eruption. The central crater of Krakatoa has always given vent to lavas of the same general type—namely pyroxene-andesites, or rather, as they should perhaps be called, dacites ; though from a lateral vent a great mass of basaltic lavas and tuffs were ejected during one epoch in the past history of the volcano. It is the pyroxene-andesites to which I especially desire to call attention ; for their study, in connection with that of other rocks of the same class, suggests a number of very interesting generalizations. The pyroxenes contained in these rocks belong to two species. The most abundant is one crystallizing in forms belonging to the ortho- rhombic system, in the composition of which the base magnesia predominates over the lime; it is a ferriferous enstatite or hypersthene. The less frequently occurring pyroxene is one crystallizing in forms of the clinorhombic system, in which lime preponderates over the magnesia: it is a true augite. Not only do these two forms of pyroxene always occur together, but they are sometimes found inter- grown with their corresponding crystallographic planes in parallel positions. From the predominating pyroxene in these rocks they 1 A paper read at the Meeting of the British Association in Manchester (September, 1887). DECADE II.—VyOL. V.—NO. I. 1 2 Prof. J. W. Judd—The Lavas of Krakatoa. are frequently described as “enstatite-andesites” or “ hypersthene- andesites.” Now these andesites of Krakatoa have been very carefully investigated, both by chemists and mineralogists, during the last four years. The memoirs of Richard,’ Renard * Sauer,® Reusch,* Oebbeke,® Von Lasaulx,® Carvill Lewis,’ Joly,® Tear, 9 Waller,!® and especially of Verbeek, Retgers, and Winkler," leave us little imadeed to be desired in this respect, We have not only a number of inde- pendent analyses of the rocks themselves, but also of each of the minerals contained in them; these having been isolated by the refined methods of modern petrography. Hach of the minerals too has been submitted to searching optical investigations, so that there are few rocks of which we can be said to know the chemical com- position and mineralogical constitution more thoroughly. _ It very fortunately happens that there are several other rocks belonging to the same general type which have also been investigated in the same thorough manner. Those that I have especially chosen for comparison are (1) the ancient and modern lavas of Santorin which have been studied by Zirkel, Karl von Hauer,” and especially by Prof. Fouqué.’ (2) The lava of Buffalo Peaks, Colorado, for the description of which we are indebted to Mr. Whitman Cross “ of the U.S. Geological Survey, and (3) the more ancient but very similar lavas of our own Cheviot Hills, which have been so carefully studied and described by Mr. Teall * and Dr. Petersen.’ Now these rocks, coming from such widely different localities, all agree in the minerals of which they are made up. They all include crystals of several species of plagioclastic felspar, the most basic or those containing a large per-centage of lime being very abundant; there are in all of them two pyroxenes, namely, ferriferous enstatite and augite, the former being present in greatest quantity ; and they all contain magnetite with some ilmenite. In addition to the porphy- ritic crystals of these minerals, there is a base or ground-mass some- times consisting of a nearly pure glass, at other times of glass which has undergone a greater or less amount of devitrification, whereby it has passed into a more or less perfectly stony mass. 1 Comptes Rendus, Seance du 19 Novembre, 1883. 2 Bull. de l’Acad. Royal de Belgique, 3re ser. t. vi. (1883). 3 Berichte der Natur, Gesellsch. zu Leipzig, 1883, p. 87. 4 Neues Jahrb. fiir Min. etc. 1884, bd. 11. 5 Tbid. 1884, bd. ii. p. 32. 6 Sitze. d. niedersch. Gesch. in Bonn, Sitz. vom 3 December, 1888, 7 Proc. Acad. Se. Philadel phia, 1884, p. 185. 8 Roy. Dublin Soe. n.s. vol. iv. p. 291. 9 “Ta Nature,’’ 1gme. Année (1885), p. 378. 10 Birm. Nat. Hist, and Microscop. Soc. Rep. and Trans. for 1883, p. vi (March, 1884). aM Krakatau, pp. 185-824. 12 Neues Jahrb. fiir Min. etc. 1866, p. 769. 18 Santorin et ses Eruptions, 1870. M4 Bull. U. 8. Geol. Survey, No. 1 (1888). \\ 15 Grou. Maa. Ser. II. Vol. X. pp. 106-109 and 252-263. 16 Mikroscopische und Chemische Untersuchungen am Knstatitporphyrit aus den Cheviot Hills, Kiel, 1884. \ Prof. J. W. Judd—The Lavas of Krakatoa. 5) That there is a very great similarity in the composition of the glassy basis of these various rocks is shown by the following analyses :— Glass of Santorin Glass of Cheviot rocks Glass of Krakatoa lava (Fouque). (Ebers in Petersen). ee Silica with Titanic acid. 71:5 ae “lei Bee 72°8 (68°8) / Alling), egg epaeoeeanseonen 16°8 14:6 14:7 = (15°9) Oxidestoi Miron! 5.255... 0'8 3°3 IS 5 (CGPI) ITN |, ERasscaceae eereecee 0°8 2°9 Meee NC iS) WIP ERTS GanngpeesonepSEbop 0-7 0°3 NO), {( il9%4)) SOUR), |. Gochabe sae eesanenede 74 S6E 2°4 Alors 3 {( ePil)) HO UASIME eae ct cs aseeteaees 2°0 5:4 Bo {Csieil)) The statement of these and subsequent analyses has been cal- culated independently of water and “loss on ignition,” not that I regard these volatile materials as being unimportant, but because the methods adopted by different chemists for their determination are so various, that their inclusion would make the comparisons less satis- factory. The analysis of the Krakatoa-glass is calculated from the bulk analysis of the pumice, compared with that of the several crystalline constituents, the proportion of each of these being known. I have placed in brackets besides this calculated analysis the actual analysis made by Retgers; but concerning this last it must be remarked that it is the analysis of the glass of the dust which fell nearly a hundred miles away from the volcano, from which some of the lighter particles had been winnowed out in its passage through the atmosphere. Moreover, it was found impossible to separate the finer grains of magnetite from this glass, so that, as admitted by its author, the silica is too low, and the iron-oxides too high. ‘The same remark probably applies, though perhaps in a less degree, to the analysis of the glass of the Cheviot-rocks. A very obvious defect in our modern methods of petrographic nomenclature and classification is that they are based on a qualitative and not on a quantitative determination of the mineralogical consti- tution of the rocks. When the relative proportions of the mineral constituents of a rock are taken into consideration, as well as their nature, we are led to some very interesting considerations. At present, so far as 1 am aware, we have no other simple method available for determining the relative proportions of the constituents of a rock than the one suggested by Sorby, that of drawing the outlines of crystals seen in section under the microscope, and then cutting out and weighing on a delicate balance the portions of paper representing each of the minerals. By obtaining a photograph instead of a drawing of the section, as was suswested by the late Sir Richard Daintree, one source of error in such determinations may perhaps be removed. Of course, if we have a bulk-analysis of the rock, and analyses of each of its mineral constituents, it is possible to calculate the proportions which these latter bear to one another. By a series of determinations of this kind, checked in a great number of different ways, I have convinced myself that the consti- tution of the Krakatoa-rock may be represented as follows :— 4 Prof. J. W. Judd—The Lavas of Krakatoa. in one hundred parts by weight. ae 91:0 Glassireseccusereccencenas 90-0 Helspars’: iassasecenscoteees 6°5 wi ( 6:0 ) IDENT: Gooeoaseabodae0005000 1:4 aoc ( 1°36) AUSILC oo cednacsbadsemeaceenl 0°6 sts ( 0°64) Magnetite .........eccececee 15 wae ( 1:00) The estimate made by Retgers, which I have placed in brackets beside my own, was based on the study of a dust which fell at Buitenzorg. But this material cannot exactly represent the original rock, seeing that during the passage of the dust through the air, the magnetite and other heavy minerals tend to fall sooner than the glass, while, on the other hand, excessively fine particles of the latter are left behind in the atmosphere. Hence, the dust which falls at any particular point cannot possibly be taken as a fair sample of the whole mass of the rock. The Krakatoa-rocks, it will be seen, consist of two very distinct materials, a crystalline portion making up one-tenth of the whole mass, and a colloid or glassy portion which forms no less than nine-tenths of the whole. The chemical composition of the whole rock and of these two constituents is as follows :— Composition of Composition of Glass Composition of Crystals rock. forming 90 °/, of forming 10 °/, of rock, rock, Silica with Titanic acid. 70:0 ves 72°8 Aa 48°7 JNU | jAonebabesonssoede 15:0 igs 14°7 19°3 Oxides of Iron ......... 4:0 om 1°8 18-0 Time asian Ue Behe 377 374 6°9 Magnesia .......0.00c8s000s 1°3 1:0 2°5 Sod anes aiencaee 4-1 4-1 3°8 Potash penuh ic sat ceceent 1-9 BB 2:2 0°8 crystalline and a glassy portion, and these have nearly the same com- position as those two portions of the Krakatoa-rock. All the rocks contain the same minerals, felspar, enstatite, augite, and magnetite ; the analyses of which yield very similar results. In all of them, too, the relative proportions of these several minerals do not appear to be very different from that we have found to exist in the Krakatoa rocks. I have already shown that the composition of the glass in these different rocks is not very dissimilar. Nevertheless the ultimate chemical composition of these various rocks, all of which are called by petrographers by the same name of “ enstatite-andesite,” or “hypersthene-andesite,” is found to differ in the most remarkable manner. This fact is illustrated by the following table :— Rock of Santorin Buffalo Cheviot — Recent lavas Rocks of dykes. Peaks lava, rocks. of Santorin, Krakatoa. Silicameeeeneeeee OMS Ow es ee BBB... dooced GEC) boos Glas, Aces 70-0 Alumina ...... 20°1 Bamecs il OS 2 Re inne PGES oeeeer TAS canine 15-0 Oxides of Iron. 11°6 ...... OB whe Dali ue ae Gd: Mean 4:0 Time ees eases DO tte FS ee ANAL VEN Sel ee 37 Magnesia ...... el! Teassaa BIG Sadana 408” oopetio ILS). gonddo 1:3 Soda wgner ADS] ie eed Owls 5 eae Gil Stee ein Ce aan cO 4:1 IRotasht ree seeee OREM eeee ey tee 308 Uh aa e PION Ceoooe 1:9 At one end of this series we have a rock which is basic in its Prof. J. W. Judd—The Lavas of Krakatoa. 5 composition, at the other end one which is distinctly acid; while the others may be fairly classed as intermediate between those types. Yet all these rocks contain precisely the same mineral constituents, and the difference in their chemical composition is clearly due to the very different proportions in which their more basic constituents, the porphyritic crystals, are mingled with the acid material, the enveloping glass. Of course any variations in the relative proportions of the different felspars, pyroxenes and of magnetite will to some extent modify the ultimate chemical composition of the rocks; but I am convinced that in all these rocks the proportion of the several minerals to one another does not vary very greatly; in all of them felspar-crystals greatly predominate over the pyroxenes and magnetite; and among the pyroxenes the orthorhombic enstatite is almost always more abundant than the clinorhombice augite. Assuming, what is certainly not far from the truth, then, that the crystalline and glassy portions of these rocks have respectively the same composition in all of them, we can calculate from the data before us the relative proportions of the crystalline and glassy portions of each of these rocks. The result is as follows :— Glassy base Crystalline portion (parts in 100). (parts in 100). Most basic dykes at Santorin ...... 10 SSan00 90 Other dykes at Santorin ............ 1O—35" tsenee 90—6d Buffalo Peaks lava ........0..00.000+ 33h asta 663 Cheviot=nocksm manent cecsecee: GEN) Mikes eee 34 Recent lavas of Santorin...:........ Sng ahis dase 50 Lavas of Krakatoa .........ses.s0e+ SOR ig Lonasters 10 It will be seen that at one end of the series we have the crystalline constituent nine times more abundant than the glass, and at the other end the glass nine times as abundant as the crystalline con- stituent. But in spite of this, the rocks according to the ordinary system of nomenclature, based on mineralogical constitution, must be called—and indeed have been called—by the same name, that of « hypersthene-andesite” or ‘“ enstatite-andesite.” Let us now turn our attention to another remarkable set of facts with respect to these lavas of Krakatoa. It is a very striking circumstance that all the materials ejected from the central vent of Krakatoa agree in a very marked manner in their chemical com- position and mineralogical constitution, both qualitatively and quanti- tatively. They all contain about 70 per cent. of silica, and are composed of 90 per cent. of base, with ten per cent. of porphyritic crystals ; these last consisting of plagioclase felspar, enstatite, augite and magnetite, always in nearly the same relative proportions. Nevertheless, while presenting this almost absolute identity in chemical and mineralogical constitution, we find among these pro- ducts of Krakatoa three distinct types of materials—exhibiting the most striking differences in their physical characters and in the mode of their behaviour during ejection. These differences are seen to be dependent on peculiarities presented by the base or ground- 6 Prof. J. W. Judd—The Lavas of Krakatoa. mass of the rocks, the crystalline or porphyritic portions being the same in all three types.* In most of the older ejections the base is of a dull reddish-grey tint, and stony texture. Under the microscope the glass of the base is seen to have undergone a great amount of devitrification, and to be filled by a mesh of microlites of felspar, pyroxene, hornblende and iron-oxides, between which minute portions of the glassy base are left. Frequently this base is cavernous, and in such cases the cavities are lined with beautiful crystallizations of quartz, tridymite and hornblende. These are probably the results of secondary alteration. The fact of water having percolated through the rock is shown by the more or less complete conversion of the magnetite into hydrated ferric oxide.: Associated with this porphyritic stony lava, we find a second type of rock, the base of which is of a jet-black colour and resinous lustre. This beautiful velvety black rock is an admirable example of a porphyritic pitchstone, and strikingly resembles the rock of the Cheviot Hills and some of the Santorin lavas. The base contains fewer microlites, but is crowded with crystallites, both belonites and trichites, and these not unfrequently, according to Retgers, form the variety of spherulites called by Rosenbusch “ felso-spherites.” The rock, moreover, often exhibits a fluidal structure. In the third type of rock occurring at Krakatoa, we find the porphyritic crystals still the same, but embedded in an almost perfect glass, which is of a rich amber-brown colour when seen in large fragments, but almost colourless in thin sections by transmitted light. This rock has been called a porphyritic obsidian. Under the microscope, the glassy base of this rock is found to contain only a very few widely-scattered microlites and crystallites. But the most striking difference between the base or ground-mass of these three types of lava becomes apparent when they are sub- jected to high temperatures. If a fragment of the stony lava or of the pitchstone be acted upon by a strong blowpipe-jet, urged by a foot-bellows, it may be rendered white-hot without exhibiting signs of fusion. But if we treat a fragment of the obsidian in the same way, we shall find that on approaching a white heat, it begins to melt, and in doing so swells up into a cauliflower-like mass, five or six times the size of the original. When this mass is cooled and examined, it is found to be a dirty brownish-white pumice, identical in all its characters with the material that was thrown out in such vast quantities during the last great eruption of Krakatoa. This identity in character is seen to be even more marked if we make thin sections of the natural and of the artificial products, and examine them under the microscope. In its behaviour the obsidian of Krakatoa behaves indeed precisely like the Marekanite of Okhotz and a glassy rock from Fife which I have previously described.’ 1 In the Report on ‘‘ Krakatoa’’ by the Royal Society Committee, plates ii. and lil. are devoted to the illustration of the characters of the rocks of Krakatoa as exhibited in microscopic sections. ® Got. Mac. Dee. III. Vol. III. (1886), p. 243. Quart. Journ. Geol. Soe. vol. xlii. (1886), p. 429. Prof. J. W. Judd—The Lavas of Krakatoa. fh In all these cases it is clear that the rocks contain a considerable proportion of volatile materials, which are given off at a high temperature. When we come to study the several varieties of the lava of Krakatoa in the field, we are struck by remarkable differences in the mode in which they must have behaved while in a liquid condition. The stony lava and the pitchstone it is seen were extruded in massive lava-streams with an almost total absence of pumice or scoriz; the obsidian, on the other hand, was almost wholly distended into a pumice, throughout which the porphyritic crystals of the rock are found entaneled. It is evident that every part of the glass has been impregnated with the volatile constituents, which by their escape have caused its conversion into pumice, for the whole of the glass is drawn out into the finest rods and plates; indeed, it is only in the case of small fragments which have been suddenly cooled before the volatile ingredients have been permitted to escape, that we are able to judge of the characters of the glass from which the pumice was formed By cutting blocks of pumice of definite size, and comparing their weight with that of masses of glass of the same size (this being easily determined when the specific gravity of the glass is known), I have been able to calculate the amount of distension which has taken place in the glass during its conversion into pumice. The more compact varieties of pumice have 34 times the bulk of the glass from which they were formed; in the more common looser varieties the distension has been at least 5 54 times the original ; and in some varieties the bulk of the air- cavities is 7, 8 or even 9 times that of the enclosing glass. The stony lavas and the pitchstones differ mainly in the amount of devitrification which the glassy base has undergone. And this we have every reason to believe was determined by the rate at which cooling took place. We find indeed every g gradation between the one type and the other, just as we do in the Cheviot Hills; at Steerhope, near Yetholm, in that district, a great lava-stream may be seen, the central portion of which consists of a stony rock, while the superficial layers graduate into well-known pitchstone. There can be little doubt that, in the same way at Krakatoa, the more rapidly cooled portions of the stony lava have formed the porphy- ritic pitchstone. But the obsidian of Krakatoa presents many very striking differences from the other two kinds of rock; and for some of these the more easy fusibility of its base affords a ready explanation. Thus, little knots of the pitchstone are often found scattered through the obsidian; and in the pumice formed from the obsidian these stand out in relief upon the abraded surfaces, in the same way as do the porphyritic crystals). Now when such knots of pitchstone are examined microscopically, the felspars in them are found to have undergone a most wonderful amount of corrosion; often the larger part of their bulk has been redissolved in the heated magma in which they have been enveloped, they are completely honeycombed, and sometimes reduced to mere skeletons. 8 Prof. J. W. Judd— The Lavas of Krakatoa. Those who regard the bulk-analysis of an igneous rock as necessarily representing the composition of the magma out of which the minerals which compose it have separated, and who further consider the successive crops of crystals formed in a rock as being determined by the alteration in the composition of the residual magma by the constant separation of the basic minerals from, it will | find it difficult to harmonize such views with the facts presented to us at Krakatoa. It is difficult, in the first instance, to account for the separation of precisely the same minerals, the felspars, pyroxenes and magnetite, in magmas of such diverse composition as is represented in the third table on page 4. On the other hand, it is a significant circum- stance that the glass of the Krakatoa-lavas is sometimes found without the porphyritic crystals; pumice formed of this glass without any enclosed crystals was certainly erupted during the eruption in May, 1883. Similar facts are recorded by Fouqué in the case of the Santorin lavas. It must be remembered, too, that the whole of the lavas of Krakatoa, and perhaps of all the volcanoes on the line of cross fissure upon which it is situated, are of an exceptional character; the ordinary enstatite-andesites of Java containing only about 55 to 62 per cent. of silica, and having a much smaller pro- portion of glass to the porphyritic crystals. In Santorin, too, we have the same difference, though somewhat less marked, between some of the older and deep-seated dykes and the modern lavas of the volcano. All of these facts point to the conclusion that after the partial separation of a magma into crystals and a colloid residue, the two may be separated by a process of liquation, and subsequently become mingled again in varying proportions. I need scarcely point out that the condition of many porphyritic crystals—eroded, broken, or frayed out in the magma in which they lie--are strongly suggestive of the same conclusion. These porphyritic crystals indeed have often the appearance of foreign materials which have been caught up by the magma in which they are now found. It is a significant circumstance that the Krakatoa-rocks, and this is true of many other rocks of the same class, do not appear to have their porphyritic crystals scattered quite at hazard through their mass. On the contrary, the felspars, pyroxenes and magnetite are seen to form little knots often intercrystallized in the midst of the vitreous base. In this respect, there is an approach to the structure for which I have proposed the name of “ glomero-porphyritic,” in which we find what looks like the association of minerals typical of one class of rock scattered through a rock of a totally different class. In the typical example of the kind which I have described fragments of troctolite appear as if scattered through an ophitic dolerite. In the case of the plutonic rocks of the Western Isles of Scotland, I have shown how frequently one or other of the constituents of a magma may segregate iocally so as to give rise to a variety of rock in which this mineral predominates. In this way gabbros are found graduating in places into rocks essentially composed of olivine, pyroxene, or felspar. Prof. J. W. Judd—The Lavas of Krakatoa. 9 Tf, as the consideration of these rocks at Krakatoa so strongly suggests, the minerals crystallized out of a magma, and the residuum of mixed silicates can be separated to a greater or less extent, and then recombined in fresh proportions, we have an explanation of the ejection from the same vent of materials differing most widely in their ultimate chemical composition, though presenting curious peculiarities in the enclosed minerals which are common to all of them. It is almost impossible to study the older and more recent ejections from Krakatoa without being driven to consider the possibility of the latter as having been to a great extent formed by the refusion of the former. Indeed the existence of knots of the unfused black glass in the midst of the modern pumices, and portions of the same material clinging to the crystals embedded in the recent obsidian, seem to render the fact of this refusion all but certain. How this refusion might have been brought about, a few very simple considera- tions will, I think, enable us to understand. The late Dr. Frederick Guthrie, whose early death was so great a loss to science, was engaged in a number of researches which have a very important bearing on questions of petrogeny, and are of great suggestiveness to the geologist. Solutions of various salts when cooled down are found to yield successive crops of crystals of ice or of the salt, until at last the remaining mixture of the two substances in a definite proportion are left behind, forming the bodies to which Dr. Guthrie gave the name of Cryohydrates. He subsequently showed that mixtures of metals or of salts behave in the same way when reduced to liquid condition by heat, and for those substances, compounds which separate out like the cryohydrates from a solution, he proposed the name of Eutectic bodies or Hutectics. The chief characteristics of these bodies is the lowness of their temperature of fusion. Dr. Guthrie himself clearly saw the importance of these considera- tions to the geologist. We are continually dealing with mixtures of salts (silicates) from which a number of definite crystallized bodies have separated out, till at last a residuum is left which consolidates at a lower temperature than any of them. The determination of the nature and composition of these eutectic silicates is a problem of the very greatest interest to petrologists. In a still later memoir, one of the last which he wrote, Dr. Guthrie attacks a closely related question which is of even greater interest and importance to the geologist. That water plays an important part in the liquefaction of the igneous masses of the Harth’s crust has been maintained by Scrope, Scheerer, Bischof, Daubrée, and many other observers, and cannot, indeed, be doubted by any one who has studied the phenomena attending the extrusion of lavas from a volcanic vent. But as to the exact réle played by the water in such molten masses, there has been much difference of opinion, and the researches of Guthrie are of the greatest importance, as throwing new light on this very interesting question. The influence of the presence of water in lowering the’ fusion 10 Prof. J. W. Judd—The Lavas of Krakatoa. points of various salts is a question which was very carefully investi- gated by Guthrie. He showed that a certain mixture of the nitrates of lead and potash had its fusion-point reduced from 8° to 4° C. by the introduction into it of a quantity of water equal to ;45th part of its weight. Still more striking are the results obtained by the study of the fusion-point of nitre as influenced by the presence of water. The following table abridged from that given by Dr. Guthrie will serve to explain this subject :— Fusion-points oF Mixtursrs or Nirre anD WATER. Nitre. Water, Fusion-points, 100 te) 600 320° C. 98°86 wee 1:14 am 300%mae 95-11 Ba 4:89 a NO 89°94 Be 10-06 He HDI 26, 84°69 ue 15°31 uy NGI. 70°14 i 20°86 an TRO 75-02 £5, 24:08 Be INGO 70°03 hae 29°07 es 97°°6 ,, There is no question here of the formation of definite compounds of nitre and water, but in the words of Dr. Guthrie ‘‘ fused nitre and fused ice are miscible in all proportions,’ the result of the increase of water being a proportional lowering of the fusion-points. “The phenomenon of fusion” is shown by Guthrie to be “nothing more than an extreme case of liquefaction by solution.” Indeed, it is impossible to define where solution ends and fusion begins ; when, for example, one part of water is present in 555 parts of a salt, it would be hard to consider the latter as dissolved in the former. Now it is impossible to doubt for one moment that the presence of water has the same effect on the fusion-points of mixed silicates that it has on other salts, though owing to the high temperatures and pressures required, experiments on these are more difficult than in the case of salts of more easy fusibility. The Zeolites consist of mixtures of silicates of alumina and of the alkalies or lime, in the same proportions as in the Felspars; but while the former contain water, the latter are anhydrous; as is well known, the Zeolites fuse at much lower temperatures than the Felspars. Nor is this true only of definite compounds as is shown by studying the fusibility of such indefinite mixtures of silicates and water as the tachylytes, hydrotachylytes, palagonites, ete. The consideration of these points leads to a clearer understanding of the method of action of water in volcanic vents. That there are serious objections to the notion of water giving rise to volcanic eruptions by finding its way through open fissures to masses of incandescent lava, has been pointed out by Scrope and other authors; and Daubrée and others have advocated the gradual percolation of water through the interstices of solid rock-masses as being an agency more in accordance with the phenomena observed. But it has always been considered necessary to assume a considerable rise in the temperature of the subterranean mass as one of the exciting causes of a volcanic outburst. A careful consideration of the results arrived at by Dr. Guthrie’s eee t -- ‘ GEOL. MAG. 1883. DECADE ITI, VoL. V. Pt. 1. Fie. 1.—Skull of Stegosaurus stenops, Marsh ; side view. Fic. 2.—The same specimen; front view. Fig, 3.—The same specimen; top view. All the figures are one-fourth natural size. From the Atlantosaurus Beds of the Upper Jurassic, Southern Colorado. GEOL. Mac. 1888. DECADE III. Vou. V. Pt. II. Fic. 1.—Dorsal spine of Stegosaurus ungulatus, Marsh; a, side view ; 4, posterior view ; ¢, section ; d, inferior view of base. Fie. 2.—Large caudal spine of same individual; a, side view; 0, front view ; other letters as above. Fie. 3.--Smaller caudal spine of same individual; 0, posterior view; other letters as above. Fie. 4.—Caudal spine of Stegosaurus sulcatus, Marsh ; side view. Fre. 5.—The same spine ; posterior view. Fie. 6.—The same spine; inner view. All the figures are one-twelfth natural size. From the Atlantosaurus Beds of the Upper Jurassic, Southern Colorado. ———————n—— OSS ’ GrEoL Mac, 1888. DECADENUE Viol. Vien bu. lhe Caudal vertebra, spines, and plate of Diracodon laticeps, Marsh; seen from the left. One-sixth natural size. a, right anterior spine; a’, left anterior spine; 0b, small caudal plate; ¢, chevron bone; yg, right posterior spine; wy’, left posterior spine; ¢, terminal vertebra; v, median caudal vertebra. From the Atlantosaurus Beds of the Upper Jurassic, Southern Colorado. Prof. O. C. Marsh—On Stegosaurus. I researches serves to convince us, however, that such rise of temperature is by no means a necessary prelude to a volcanic out- burst, but that the percolation of water to a centre of igneous activity is in itself sufficient to serve as an exciting cause. If we were to imagine a mass of solid nitre lying at some depth within the earth’s crust, and having a temperature of 260° C., such a mass would be solid and inert. Butif, without raising the temperature, a quantity of water, equal to five per cent. of the weight of the nitre, were introduced into it, then the whole would become liquid and the tendency of the heated water to relieve itself from the pressure might give rise to all the phenomena of a volcanic outburst. What is true of nitre is equally true of the mixed silicates composing lavas, which are at much higher temperatures. ‘The admission of water to such a mass of mixed silicates at a temperature below its point of fusion would cause it to become liquid and thus give rise to the phenomena of eruption. In the case of the Krakatoa-lavas, the anhydrous varieties probably existed quite solid at tolerably high temperatures ; but the gradual percolation of water into their mass (and the evidences of such percolation, are seen in the hydrated condition of the minerals composing it) would render the whole liquid, without the necessity for any rise in temperature. I1.—Tue Sxuut anp Dermat Armour oF STzZGOSAURUS. By Professor O. C. Marsu, Ph.D., LL.D. (PLATES I. II. III.) N various numbers of the “American Journal of Science,” the writer has given the more important characters of the skeleton of the Steyosauria, and has indicated the relations of this group to the other known Dinosauria.!. The discovery of additional specimens of Stegosaurus, one of them nearly complete, furnishes material to greatly enlarge our knowledge of the skull and dermal covering of this genus, and some of the new facts are given in the present article. The results of the entire investigation of this group will be brought together in a monograph now in preparation, by the writer, for the United States Geological Survey. The lithographic plates for this volume, sixty-five in number, are nearly all printed, and the figures of the skull here given are taken from these plates. Tue Sxuuz. (Plate 1.) The skull of Stegosaurus is long and slender, the facial portion being especially produced. Seen from the side, with the lower jaw in position, it is wedge-shaped, with the point formed by the pre- maxillary, which projects well beyond the mandible, as shown in Fig. 1, Plate I. The anterior nares (a) are large, and situated far in front. The orbit (6) is very large, and placed well back. The 1 « American Journal of Science,’’ vol. xiv. p. 513, Dec. 1887; vol: xix. p. 253, March, 1850; vol. xxi. p. 167, Feb. 1881; vol. xxiii. p. 83, Jan. 1882; and vol. xxiv. p. 410, Noy. 1887. 12 Prof. O. C. Marsh—On Stegosaurus. lower temporal fossa (c) is somewhat smaller. All these openings are oval in outline, and are on a line nearly parallel with the top of the skull. In this view, the lower jaw covers the teeth entirely. Seen from above, as shown in Fig. 3, Plate I., the wedge-shaped form of the skull is still apparent. The only openings visible are the supra-temporal fosse (e). The premaxillary bones (pm) are short above, but send back a long process below the narial orifice. The nasal bones (x) are very large, and elongate. They are separated in front by the premaxillaries, and behind, by anterior projections from the frontal bones. The prefrontals (pf) are large, and are placed between the nasals and the prominent, rugose supra- orbitals (so). The frontals are short, and externally join the post- frontals (fp). The parietals are small, and closely codssified with each other. Viewed from in front, the skull and mandible present a nearly quadrate outline (Pl. I. Fig. 2), and the mutual relations of the facial bones are well shown. In this view is seen, also, the predentary bone (pd), a characteristic feature of the mandible in this genus. The lateral aspect of this bone is shown in Fig. 1. The teeth in this genus are entirely confined to the maxillary and dentary bones, and are not visible in any of the figures here given. They are small, with compressed, fluted crowns, which are separated from the roots by a more or less distinct neck. The premaxillary and the predentary bones are edentulous. The present skull belongs to the type specimen of a very distinct species, which the writer has called Stegosaurus stenops. The skull and nearly complete skeleton of this specimen, with nearly all the dermal armour in place, were found almost in the position in which the animal died. This animal was much smaller than those representing the other species of this genus. Its remains were found in the Atlantosaurus beds of the Upper Jurassic, in Southern Colorado. In this geological horizon, all the known American forms of Stegosauria have been discovered. Tue Dermat Armour. The osseous dermal covering of Stegosaurus was first described by the writer from specimens found associated with several skeletons, but not in place, and hence the position of the various parts was a matter of considerable doubt. Subsequent discoveries have shown the general arrangement of the plates, spines, and ossicles, and it is now evident that, while all the group were apparently well pro- tected by offensive and defensive armour, the various species, and perhaps the sexes, differed more or less in the form, size, and number of portions of their dermal covering. This was especially true of the spines, which are quite characteristic in some members of the group, if not in all. The skull was evidently covered above with a comparatively soft integument. The throat and neck below were well protected by small, rounded and flattened ossicles having a regular arrangement in the thick skin. One of these ossicles is shown in Woodcut Fig. 1. Prof. O. C. Marsh—On Stegosaurus. 13 The upper portion of the neck, back of the skull, was protected by plates, arranged in pairs on either side. These plates increased in size farther back, and thus the trunk was shielded from injury. a b c le eee eat Q ee Fic. 1.—Gular plate of Stegosaurus ungulatus, Marsh; a, superior view; 3, side view ; ¢, inferior view. From the pelvic region backward, a series of huge plates stood upright along the median line, gradually diminishing in size to about the middle of the tail. One of these is shown in Woodcut Fig. 3. a Fic. 2.—Caudal plate of same individual; a, side view; 4, end view of base ; c, view of opposite side; d, thin margin; ¢, rugose base; f, and f’, surface marked by vascular grooves. Some of the species, at least, had somewhat similar plates below the base of the tail, and one of these bones is represented in Woodcut Fig. 2. Fic. 3.—Dorsal plate of same individual; a, right side; 4, thick basal margin ; c, left side; other letters as in last figure. All the figures are one-twelfth natural size. The offensive weapons of this group were a series of huge spines arranged in pairs along the top of the distal portion of the tail, which was elongate and flexible, thus giving effective service to the spines, as in the genus Myliobatis. In Stegosaurus ungulatus, there were four pairs of these spines, diminishing in size backward. Two of the larger of these are 14 Prof. O. C. Marsh—On Stegosaurus. shown on PI. IJ. Figs. 2 and 3, In some other forms there were three pairs, and in S. stenops but two pairs have, as yet, been found. In one large species, Stegosaurus sulcatus, there is at present evidence of only one pair of spines. These are the most massive of any yet found, and have two deep grooves on the inner face, which distinguish them at once from all others known. One of these grooved spines is represented on PI. II. Figs. 4, 5, and 6. The position of these caudal spines with reference to the tail is indicated in the specimen figured on Pl. III., which shows the vertebra, spines, and plate, as found. The American genera of the Stegosauria now known are Stegosaurus, Hypsirhophus and Diracodon. Of the former there are several well- marked species besides S. armatus, the type. Of the latter genus but one is known at present, Diracodon laticeps, the remains of which have hitherto been found in Wyoming at a single locality only, where several individuals referred to this species have been discovered. Aside from the form of the skull, these specimens have in the fore foot the intermedian and ulnar bones separate, while in Stegosaurus these carpals are firmly codssified. All the known American forms appear to have the second row of carpals unossified, and five digits in the manus. In the hind foot, the astragalus is always codéssified with the tibia, even in very young specimens, while the calcaneum is sometimes free. The second row of tarsals is not ossified in any of the known specimens. Only four digits in the hind foot are known with certainty, and one of these is quite small. All forms have at least three well-developed meta- tarsals, which are short and massive, but longer and much larger than the metacarpals. Most of the bones originally referred to the hind foot of Stegosaurus ungulatus, and figured as such (Amer. Journ. Sci. vol. xxi. pl. viil.), although found with the posterior extremities, subsequently proved to belong to the fore foot of another larger species. In one large specimen, of which the posterior half of the skeleton was secured, no trace of dermal armour of any kind was found. If present during life, as indicated by the massive spines of the ver- tebree, it is difficult. to account for its absence when the remains were found, unless, indeed, the dermal covering had been removed after the death of the animal, and previous to the entombment of the skeleton where found. In this animal, the ilia were firmly codssified with the sacrum, thus forming a strong bony roof over the pelvic region, as in birds. This specimen represents a distinct species, which the writer has pamed Stegosaurus duplex. It was originally referred by him to S. ungulatus, and the pelvic arch was figured under that name.’ In the sacrum of this species, each vertebra supports its own transverse process, as in the Sauropoda, while in S. ungulatus these processes have shifted somewhat forward, so that they touch, also, the vertebrz in front, thus showing an approach to some of the Ornithopoda. The great weight of the armour in Stegosaurus, taken in connection 1 Amer. Journ. Sci, vol. xxi. pl. vii. Feb. 1881. Prof. H. A. Nicholson—Organisms in Paleozoic Limestones. 15 with the massive and solid bones of the skeleton, and, especially, the enormous vertical extent of the compressed tail, indicate an aquatic life. This opinion was expressed by the writer in describ- ing the first specimen found, and the discoveries since made have done much to confirm it. That these reptiles moved freely on land, also, is quite probable. Other genera of the group may have lived mainly upon the land. The large number of specimens of the Stegosauria now known from the American Jurassic, and the fine preservation of some of the remains, enable us to form a more accurate estimate of the relations of the group to the other Dinosaurs, than has hitherto been possible. The presence of a predentary bone, and the well-developed post- pubis, are important characters that point to the Ornithopoda as near allies, with a common ancestry. These positive characters are sup- plemented by some points in the structure of the skull, and the form of the teeth. There are, however, a large number of characters in which the Stegosauria differ from the Ornithopoda, and among these are the following :— (1) All the bones of the skeleton are solid. (2) The vertebre are all biconcave. (3) All the known forms have a strong dermal armour. (4) The second row of carpals and tarsals are unossified. (5) The astragalus is codssified with the tibia. (6) The spinal cord was greatly enlarged in the sacral region. The relations of these two groups to each other and to the rest of the known Dinosauria will be fully discussed by the writer in his monograph on the Stegosauria. New Haven, Conn., October, 1887. IIJ.—On cEertTAIN ANOMALOUS ORGANISMS WHICH ARE CONCERNED IN THE FORMATION OF SOME OF THE PaL#ozo1c LIMESTONES. By H. Atteyne Nicuotson, M.D., D.Sc., F.G.S., Regius Professor of Natural History in the University of Aberdeen. ee many of the Paleozoic limestones are more or less exten- sively composed of the skeletons of various Invertebrate animals, sometimes in a perfect condition, sometimes more or less largely fragmentary, has long been known. In certain instances a microscopic investigation of these ancient calcareous sediments may fail to demonstrate the presence of organic remains, or may reveal but few of these. Thus there occur beds of lithographic limestone in the Paleeozoic series which would seem to be simply of the nature of very finely levigated calcareous mud, the component grains of which were, however, doubtless derived, in the first instance, from the calcareous skeletons of animals. Again, it commonly happens, even in examples where the rock may to all appearance be little altered, that a limestone may be found on examination by means of thin sections to have undergone secondary crystallization, with the result of a more or less complete obliteration of the organic remains 16 Prof. H. A. Nicholson—Organisms in Paleozoic Limestones. of which it was originally made up. Such secondary crystallization is generally the result either of the application to the rock of pressure, or of dolomitisation. In the great majority of the ordinary Palzo- zoic limestones, it is, however, generally easy to show that the rock is essentially organic, in the sense that it is extensively or essen- tially composed of the calcareous skeletons of living beings. The organisms which are principally concerned in the formation of the Paleozoic limestones are, as is well known, the Crinoids, the Fora- minifera, the Stromatoporoids, and the Corals. Less important, though nevertheless sometimes taking a conspicuous part in the composition of the older limestones, are the Brachiopods, the Polyzoa, various groups of Molluses, and the Ostracodous Crustaceans. In the present communication I wish to direct attention more particularly to some organisms which are largely concerned in building up certain of the Paleozoic limestones, but which cannot at present be definitely referred to a place in any of the groups of animals above mentioned. The organisms in question are curiously like one another in general form and mode of occurrence, at the same time that they differ entirely in their internal structure ; and they have been referred to the anomalous genera Mitcheldeania, Wethered, Solenopora, Dyb., and Girvanella, Nich. and Eth., jun. Genus Mircuenpeanta, Wethered, 1886. The organisms which compose the genus Mitcheldeania have the form of small rounded or oval calcareous masses, made up of capillary tubes, of an oval or circular shape, which radiate from a central point or points. and are intermixed with an interstitial tissue of very much more minute branching tubuli (Fig. 1). The larger tubes may be considered as zodidal tubes, and the proportion which they bear to the interstitial tubuli varies in different specimens, and in different parts of the same specimen. Usually, the zooidal tubes occupy comparatively extensive regions of the skeleton, being separated from one another by a limited number of the minute tubuli; the latter also occupying irregular tracts to the exclusion of the large tubes (Fig. 1, A and C). The zoodidal tubes further communicate with one another by means of large irregularly-placed foramina, resembling the “mural pores” of the Favositide (Vig. 1, G); and they occasionally exhibit a few irregular transverse parti- tions or ‘‘tabule.”” Increase appears to be by fission. The intersti- tial tubuli communicate with one another by irregular pores in their walls, or by branching, and they constitute a sort of “ coenenchyma,” in many respects resembling the ccenosarcal tissue of Allopora (see Bicga@)): The genus Mitcheldeania was founded by Mr. Wethered (Grot. Mage. 1886, Dee. III. Vol. II. p. 535) for the reception of certain singular little bodies which occur abundantly in parts of the Carbon- iferous Limestone of the Forest of Dean. The single species recognized was described by Mr. Wethered under the name of M. Nicholsoni,! and the author was good enough to submit some of his 1 Mr. Wethered re-described and re-figured the species in the ‘ Proceedings of the Cotteswold Club,’ 1887. Prof. H. A. Nicholson—Organisms in Paleozoic Limestones. 17 material to me for examination, thus enabling me to prepare for myself a series of thin sections. Owing, however, to its small size and to the minuteness of its component tissues, the investigation of M. Nicholsoni is attended with great difficulties; and I have been able recently to make a much more satisfactory study of the characters of the genus from a much larger species, which occurs abundantly in parts of the Carboniferous series of the South of Scotland, and which I shall describe under the name of M. gregaria. oe i oe ~) ¥ * Gr) Fic. 1.—Minute structure of the skeleton of Mitcheldeania gregaria, Nich. A. Tangential section of part of the skeleton where the interstitial tubuli are com- paratively few in number, enlarged 20 times. B. Vertical section of the same, similarly enlarged. C. Tangential section of part of the organism where the interstitial tubules are greatly developed, enlarged 20 times. D. Vertical section of a few tubes, enlarged 40 times. E. Vertical section of zodidal tubes, with interstitial branching tubuli, enlarged 40 times. F. Vertical section of a part with few interstitial tubes, enlarged 60 times, showing connecting pores and ‘‘tabule.’? G. Tangential section of a similar part, enlarged 80 times. MITCHELDEANIA GREGARIA, n. sp. Figs. 1 and 2. The organism occurs in the form of small rounded masses, approximately spherical in shape, and averaging about 10 milli- métres in diameter, some examples exceeding this, while others do not reach this size. There are no traces of a peduncle of attach- ment, nor do sections exhibit any foreign body which might have served as a nucleus of growth. The surface may be smooth, but is DECADE II.—VOL. Y.—NO. I. 2 18 Prof. H. A. Nicholson—Organisms in Paleozoic Limestones. in general more or less lobulated, exhibiting under a lens, in well- preserved specimens, exceedingly minute pores. The skeleton is composed of radiating capillary tubes, disposed in concentric strata, and having a diameter of from +1; to +5 of a millimétre. In large portions of the skeleton these zooidal tubes are placed near to one another, being separated only by a single row of smaller tubuli (Fig. 1, F and G), or being in direct contact. In other portions of the skeleton, the large tubes may be absent or may be scattered irregularly among very minute tubuli. ‘These interstitial tubulli (Fig. 1, A and C) have a diameter of 31; of a millimétre, or less, and usually occupy irregular patches of various sizes, between the groups of larger tubes. Vertical sections show that the large zooidal tubes communicate with one another by oval or circular apertures, of comparatively large size, and uniserially disposed, the general aspect of these resembling that of the “mural pores” of the Favositide (Fig. 1, F). Very commonly, indeed usually, the zodidal tubes appear to be free from internal partitions, but transverse plates, resembling ‘“tabulee,’ can sometimes be recognized here and there. No structures of the nature of radiating “septa” are present in the tubes. The interstitial tubuli appear to communicate with one another by minute pores; and vertical sections show that they commonly branch irregularly, and anastomose with one another (Fig. 1, HE). Hence, in tangential sections of the areas occupied by the tubuli, there are generally seen minute branching canals inter- spersed among the cut ends of the tubuli, and resembling in aspect the coenosarcal canals of Allopora and Millepora, and of many Stromatoporoids (see Fig. 1, C). This remarkable organism occurs in vast numbers in the Lower Carboniferous Series of parts of the South of Scotland and the North-west of Northumberland, and forms in places extensive beds of limestone. It was first brought under my notice by my friend Mr. Benjamin Peach, who informs me that it has a wide distribu- tion ; but the only locality in which I have personally collected it is Fie. 2.—A fragment of limestone from the Lower Carboniferous Series of Kershope Foot, largely composed of Mitcheldeania gregaria, of the natural size. Prof. H. A. Nicholson—Organisms in Paleozoic Limestones. 19 Kershope Foot, in Roxburghshire. Here beds of the limestone are more or less extensively composed of the bullet-shaped or grape-like skeletons of this singular fossil (Fig. 2). There is no room to doubt that M. gregaria is congeneric with M. Nicholsoni, Wethered, from the Carboniferous Limestone of the Forest of Dean. It is, however, clearly a distinct species, not only being constantly of much larger size, but being also distinguished by marked structural peculiarities. Thus, M. Nicholsoni rarely ex- ceeds four or five millimétres in length, and is very irregular in form, commonly enveloping other organisms, or forming crusts on foreign bodies. The zodidal tubes in this species are also proportionately large in point of size, are few in number and irregular in distribution, and are separated by a great proportionate abundance of minute interstitial tubuli. Thin sections of Mitcheldeania gregaria have a general resemblance to corresponding sections of certain Monticuliporoids, but none of the latter make any approach to the present form as regards the minuteness of the component tubes of the skeleton. The presence of connecting-pores between adjacent zodidal tubes and of an interstitial canal-system would also separate Mitcheldeania structurally from the Monticuliporoids. In spite of the extreme minuteness of its tissues, the genus Mitcheldeania may, I think, be referred with tolerable certainty to the Celenterata. Admitting its Ccelenterate affinities, it would seem almost certain that the genus must be placed in the series of the Hydrozoa. There is, however, no known group of this class within which Mitcheldeania can be satisfactorily located. Its closest affinities seem to be with the Hydrocorallines, and in this. connection I would particularly draw attention to the resemblance of the interstitial tissue of Mitcheldeania to the ccenenchymal tissue of certain species of Allopora. In one species of the latter genus which I have investigated the coenenchymal tissue is not only very similar to that of Mitcheldeania, but is not so very much grosser in structure. On the other hand, all the known Hydrocorallines possess zooidal tubes which are enormously larger than those of Mitcheldeania; and there are other morphological features in the latter genus which would preclude its being actually placed, with our present knowledge, in the group of the Hydrocoralline. Genus SoLenopora, Dybowski, 1877. This genus includes calcareous organisms, which present them- selves in masses of varying form and irregular shape, and are composed wholly of radiating capillary tubes arranged in concentric strata. The tubes are in direct contact, and no “coonenchyma,” or inter- stitial tissue, is present. The tubes are thin-walled, irregular in form, often with undulated or wrinkled walls, without mural pores, and furnished with more or fewer transverse partitions or “tabule.”’ . No radiating “septa” are developed, but the type-species exhibits more or fewer inwardly directed septiform processes, which are the result of the rapid fission of the tubes (see Fig. 3, C). 20 Prof. H. A. Nicholson—Organisms in Paleozoic Limestones. The genus Solenopora was originally described by Dr. Dybowskt (Cheetetiden der Ost-Baltischen Silur-Formation, p. 124, 1877) for the reception of a singular fossil which is of common occurrence in the Ordovician limestones of certain localities in Esthonia.. The structure of this organism has been fully dealt with by Mr. R. Etheridge, jun., and myself (Gron. Mac. Dec. III. Vol. II. p. 529, PL. XIIL.), and we have shown its identity with the forms previously described by Mr. Billings as Stromatopora compacta, and by our- selves as Tetradium Peachii. The species stands, therefore, now as Solenopora compacta, Billings, the Scotch examples remaining as a variety, for which the name Peachii may be employed. B Fic. 8.—A, A small specimen of Solenopora compacta, Billings, from Saak, Esthonia, of the natural size. B, Surface of a piece ot limestone largely made up of small specimens of the same, from the same locality, of the natural size. C, Tangential section of the same, enlarged about 36 times. JD, Vertical section of the same, similarly enlarged. SoLENopoRA compacta, Billings, sp. Fig. 3. This species has been so fully treated previously (loc. cit. supra), that it is unnecessary for me to enter here into any discussion of its characters. The accompanying illustration (Fig. 3) will sufficiently indicate its general form, mode of occurrence, and minute structure. As a species it is distinguished by the size of its component tubes (which vary in diameter from ;’y to ‘5 of a millimetre), and by the facts that the tubes are irregular in shape, have undulated walls, and are furnished with more or less numerous septiform processes due to fission (Fig. 8, C and D). It has been already shown by Mr. R. Etheridge, jun., and myself (loc. cit.), that Solenopora compacta, Billings, is very widely dis- tributed in the Ordovician rocks, and that it played a very important part in the formation of certain of the limestones of this period. Prof. H. A. Nicholson—Organisms in Paleozoic Limestones. 21 We recognized its occurrence in the Trenton and Black River Lime- stones of North America, in limestones of corresponding age in Esthonia (“ Jewesche Schichten”’), and in the Ordovician limestone of Oraighead, near Girvan, in Ayrshire. To the facts previously recorded with regard to the range of this remarkable fossil, I can now add some further information of interest. Thus my friend Prof. Lapworth has recently submitted to me a number of examples of this species, of unusually large size, which he has collected in the “Hoar-Edge Limestone” of Shropshire. This discovery has the effect of extending the known range of Solenopora compacta in Britain from the Ordovician area of Ayrshire to that of the classical district of the West of England. Again, I find that the fossils described by Mr. S. A. Miller, from the Cincinnati group of North America under the name of Stromatocerium richmondense (Journ. Cincinnati Soc. Nat. Hist. vol. v.) are in part referable to Solenopora, and are undistinguishable from S. compacta, Bill., sp. Mr. H. O. Ulrich has been kind enough to furnish me with a number of speci- mens from the Cincinnati group of Indiana, which he regards as referable to the so-called Stromatocerium richmondense. These speci- mens are in the form of small irregular calcareous masses, very closely resembling one another in general appearance, but differing so far that, when broken across, some show a conspicuous composition out of concentric layers, while others are more compact and uniform in texture. In point of fact, the specimens, in spite of their apparent similarity, are not all the same. Some of them are referable to Solenopora compacta, Bill.; others are referable to a species of Girvanella (= Strephochetus, H. M. Seeley) ; while others are com- posed of both these organisms growing in superimposed colonies. SoLENOPORA ? FILIFORMIS, n. sp. Fig. 4. In the Ordovician limestone of Craighead, near Girvan, there occurs a fossil which I may provisionally describe under the above name, and which is associated with the preceding in the formation of the limestone. It is often present in great abundance in the lime- stone, but its internal structure is commonly much obscured, or even destroyed by crystallization. It presents itself sometimes in the form of small rounded or irregular nodules, or, at other times, as lobate or ramified masses of considerable dimensions. Viewed with a powerful magnifying glass it appears to be quite compact, or obscurely fibrous; but when examined microscopically, it is seen to be composed of exceedingly minute capillary radiating tubes disposed in concentric strata. The tubes are thin-walled, regularly prismatic in shape, without mural pores or radiating septa, but furnished with numerous transverse partitions or “tabule ” (Fig. 4). The average diameter of the tubes is about #; of a millimétre. Increase of the tubes appears to take place by fission, but the tubes do not exhibit inward septiform processes, such as are so character- istic of the cross-sections of the tubes of Solenopora compacta. I have some doubts about the reference of this fossil to the genus 22 Prof. H. A. Nicholson—Organisms in Paleozoic Limestones. Solenopora, as it differs from the type of the genus in important structural characters. This is more particularly seen in the regularly prismatic form of the component tubes of the skeleton, and in the total absence of the septa-like process produced in Solenopora compacta by the commencing fission of the tubes. At the same time, it agrees entirely with S. compacta in its general form and mode of occurrence, and especially in its being composed of imperforate, tabulate tubes of excessive minuteness. Upon the whole, therefore, it seems safest to place it temporarily in the genus Solenopora. Fie. 4.—A, Tangential section of Solenopora ? filiformis, Nich., from the Ordovician limestone of Craighead, Girvan, enlarged about 60 times. B, Vertical section of the same, similarly enlarged. It cannot be said that the present species throws much fresh light upon the systematic position of the genus Solenopora. If viewed without reference to the size of its tubes, it might quite well be regarded as a Monticuliporoid, and might be placed. under the genus Monotrypa. The extraordinary minuteness of the tubes would seem, however, of itself, sufficient to preclude a reference of this fossil to the Monticuliporoids. If, however, we admit that the genus Mitcheldeania may be referred to the Hydrozoa, we can get over one of the principal difficulties attending the supposition that the genus Solenopora is referable to the same great class—the difficulty, namely, that no known Ceelenterate possesses a skeleton of such an excessively minute character. Upon the whole, therefore, I am inclined to think it may be tolerably safe to regard Solenopora, Dyb., as representing a peculiar extinct group of Hydrozoa, though I do not think that the evidence upon this point is in any way conclusive. Genus GirvaNeLLA, Nicholson and Etheridge, Jun., 1880. Fig 5. Largely concerned in the formation of the Ordovician limestones of Ayrshire, and commonly associated with the preceding, is another remarkable organism which was described in 1880 by Mr. R. Ktheridge, jun., and myself, under the new generic and specific name of Girvanella problematica (Mon. Sil. Foss. Girvan, p. 28, pl. ix. stone at Craighead, sometimes being the principal agent in the fig. 24). This curious fossil occurs in great numbers in the lime- formation of the rock, and presents itself in the form of small Prof. H. A. Nicholson—Organisms in Paleozoic Limestones. 23 rounded or irregular nodules, which vary in diameter from less than a millimétre to more than a centimétre. The larger examples (Fig. 5, A) show a distinctly concentric structure, visible even to the naked eye, but the most powerful lens fails to show any obvious internal structure in fractured or weathered surfaces. Hxamined microscopically by means of thin sections, the nodules of Girvanella are seen to consist of exceedingly minute circular tubes, endlessly contorted and bent, and twisted together in loosely reticulate or vermiculate aggregations (Fig 5, B). The tubes vary in their size from 31; to =; of a millimétre in diameter. Most commonly they are about ;4; mill. in diameter. The walls of the tubes have a granular aspect, as if formed of exceedingly minute granules, but it is not possible to determine absolutely whether they are or are not truly calcareous in composition. No internal partitions are visible in the tubes, nor do they exhibit any perforations in their walls. A Fic. 5.—A, Fragment of limestone from the Ordovician rocks of Craighead, Girvan, of the natural size, showing numerous exceptionally large masses of Girvanella problematica, Nich. & Eth. jun. B, Section of a minute mass of Girvanella, enlarged about 60 times. In the original description of Girvanella problematica by Mr. R. Etheridge, Jun., and myself (loc. cit.), the genus was provisionally referred to the Rhizopoda, and was regarded as related to the arenaceous Foraminifera. This view of the affinities of Girvanella, from which I see no reason to depart, was the one taken by Mr. H. B. Brady, to whom we had submitted our specimens ; and this dis- tinguished authority compared Girvanella with the recent Hyperammina vagans, figures and descriptions of which have now been published (see Chall. Reports, vol. ix. p. 260, pl. xxiv. figs. 1-9). The same author’s great work on Foraminifera contains, however, another genus of arenaceous Foraminifera which admits, perhaps, of an even closer comparison with Girvanella than does the form above mentioned. I allude to the remarkable form described by Mr. Brady under the name of Syringammina fragilissima (Chall. Reports, vol. ix. p. 242, woodcut), in which the organism is free, and consists of a mass of minute arenaceous tubes disposed in concentric layers, and having a generally radiate arrangement. 24° A. C. G. Cameron—Hertfordshire Subsidences. In Britain, the genus Girvanella has, so far, only been recognized as occurring in the Ordovician limestones of Ayrshire. I have, however, found some of the Carboniferous limestones of the North of England to contain largely an ill-preserved organism which will, I think, prove to be referable to Girvanella. As previously pointed out, the genus occurs in the Ordovician rocks of North America. This is shown by the fact that certain of the specimens from the Cincinnati Group of Indiana sent to me by Mr. E. O. Ulrich as belonging to the Stromatocerium richmondense of Mr. 8. A. Miller, prove on examination to belong toa species of Girvanella, specifically distinct, | think, from our British species, as shown by the greater minuteness of “its tubes. I see, also, no reason to doubt that the fossils from the Chazy Limestone of North America, for which Prof. Henry M. Seeley has proposed (Amer. Journ. Sci. and Arts, 1885, vol. xxx. p. 395, 1885) the new generic name of Strephochetus, are in reality referable to the genus Girvanella. It is probable that the Chazy form (Strephochetus ocellatus, Seeley) is specifically distinct from Girvanella problematica, but its generic identity appears to be indubitable.'. Prof. Seeley seems disposed to think that the curious fossil described by Prof. James Hall, from the Calciferous Limestone, under the name of Cryptozoén proliferum (Thirty-sixth Ann. Rep. of the State Cabinet, pl. vi. 1884), may be related to Girvanella ; but I ~ cannot think that such a relationship—supposing it to exist—can be one of generic affinity. The fossil for which Prof. Hall has proposed this name is not only comparatively gigantic in point of size, but its internal structure, so far as may be judged from the incomplete provisional diagnosis given by its author, is altogether different, since it is stated to consist of branching and anastomosing canaliculi. Lastly, with regard to Prof. H. M. Seeley’s reference of Girvanella (=Strephochetus) to the calcareous sponges, it need only be said that the structure of the genus, so far as recognized, shows nothing which would warrant such a reference, and that it would be essential to the establishment of this view, according to our modern lghts, that the organism should be proved to possess definite spicules. ITV.—HeERTFORDSHIRE SUBSIDENCES. By A. C. G. Cameron. UBSIDENCES are by no means unusual amongst the arable lands in the Chalk districts of this county. No one, who has travelled in these parts, can have failed to notice the numerous holes and dells dotted about the fields in all directions, many of which have fallen in, or will do'so, in course of time. Nearly all of them mark spots where the Chalk has been dug up for chalking the land, which is then said to work better.” On the crown of some hill or ridge, it is no uncommon sight to 1 Dr. Hinde has already pointed out that Strephochetus, H. M. Seeley, is identical with the previously described Girvanella, and has further shown that the Siphonema of Dr. Bornemann, supposed by its describer to be a calcareous Alga, is likewise a synonym of Girvanelia (Grout. Maa. 1887, Dec. III. Vol. IV. p. 227). 2 Gravel soils, such as fringe the modern alluvium of rivers and streams, are chalked as well as the stronger soils. A. O. G. Cameron—Hertfordshire Subsidences. 25 find a windlass and bucket erected over a circular hole or shaft sunk deep in the Chalk, while a man at the bottom, working right and left of him, sends bucketfuls of dazzling, white chalk to the surface, which is wheeled away in barrows, and deposited in heaps close to one another, in the field where the shaft has been sunk, to be after- wards broken up, and lain about the place. When all the chalk that is required has been dug up, the windlass disappears, and the hole is filled up to the original surface level, in order that no unnecessary unevenness should occur to mar the ploughing. Gradually however, a subsidence takes place, as the material, with which the hole was filled, settles down in the cavity prepared for it, and then for a time, a basin-shaped hollow marks the site of the shaft. Suddenly a deep ring-like orifice, the sides of which show a clear section of the earth and stones, with which the hole was filled, appears at the bottom of the pit, and a veritable swallow-hole is formed on the spot. If it is only a subsiding hole, that is, one that may go down at any moment, a short funnel or pipe is seen, without the ring-like orifice and clean cut sides. Harvest is the time, I am told, when these pits most frequently fall- in; but as the subsidences also occur during rainy seasons, when water wells up or accumulates at the bottom, I am inclined to think the reported falling in at harvest time is greatly accounted for by reason of more people being in the fields then to observe them than at any other time. Holes are being re-filled this autumn about here, that have required filling several times before. In some parts of the county “ doming” is resorted to for covering the holes, thereby obviating the periodical filling up, which may require doing yearly. A pit to be domed, is first nearly filled up to the original surface-level, at least presumably so—and then arched over with brickwork and covered with earth. This plan is said to cost no more than the other, but the latter is the safer of the two. A labourer informed me that somewhere in the Baldock country, a domed hole once caved in when a ploughman and lad with three horses were crossing it. The two attendants had a narrow escape for their lives, the three horses were killed. Poles are sometimes put up to show the sites of these pits. The foregoing brings to my recollection much that is in common with the ‘natural pits’ at Ripon,! where it will be remembered a haystack disappeared down a cavity” that suddenly opened in the limestone, during the time the haymakers had adjourned for dinner. Doubtless some Hertfordshire subsidences® are as natural as those at Ripon—due to the dissolution of the strata by acidulated waters. Semicireular holes in the chalk filled with brickearth, often seen 1 See Natural Pits at Ripon, by Rev. Stanley Tute, Proc. Yorks. Geol. and Polyt. Soc. 1869. Also ‘Subsidences over Permian Limestone,’ A. C. G. Cameron, Rep. Brit. Assoc. York, 1881, and Proc. Yorks. Geol. and Polyt. Soc. vol. vii. pt. iv. 2 Locally named ‘‘shoots’’ and “ earthquakes.”’ 3 See ‘‘ Nature,’ vol. xxxvii. Dec. 8, 1887, On an Earthquake in England, by Worthington G. Smith. 26 =T. M. Reade—Hffects of Temperature on Terra- Cotta. where any considerable section of Chalk is exposed, as in a rail or road cutting, indicates natural subsidences whose origin may be traced to causes similar to those at Ripon. If it were possible to see the surface of the Chalk, bared of its superficial covering of clay, loam, etc., it would, I imagine, be singularly convex and concave. In digging pits, the chalk is is sometimes found close to the surface at one side of the shaft, but cannot be found at twenty or even thirty feet on the other side. V.—Errects or ALTERNATIONS OF TEMPERATURE ON TERRA CorTa CopINGs SET IN OxMENT AS AN ILLUSTRATION OF A THEORY OF Mountain Bouruprina. T. Mretuarp Reape, C.E., F.G.8., F.R.1.B.A. LSEWHERE I have shown that metals under certain conditions when subjected to changes of temperature undergo permanent deformation. Thus sheets of lead ridge up and fold even under the influence of atmospheric changes, as may be seen by the examina- tion of any old lead flats or cutters. The cumulative effect of small but repeated changes of temperature is very striking, and I have used it in illustration of what I conceive to be the true explanation of the ridgings up of the earth’s crust called mountain ranges. The examples given’ of the effects of alternations of temperature are mostly in metals, but I have also shown that other materials not ductile are affected in the same way, in a lesser degree. A very remarkable example has lately come under my notice? of the lengthening of a terra cotta coping, which it appears to me can only be explained on the same principle. The coping in question which, is freely exposed to the direct rays of the sun, consists of two courses of red Ruabon terra cotta bricks set in cement upon a fence wall, built with common bricks in mortar a brick and a half thick. The courses are level, but, in consequence of the inclination of the road, the coping is stepped down at intervals, so that the under-course of bricks of one length is just gripped and held in position by the top course of the next length of coping. It will thus be seen that it must constitute by liability to lifting a more delicate test than ordinary of any increase of length that might take place in the coping. When I examined the coping—and I have looked at it over and over again—the end portion of one length abutting against the next length at the drop in the level was thrown up into an anticlinal of about 6 ft. span ; the coping bricks being lifted in the highest part one inch from their bed. There was a fracture at the crown of the anticlinal, and another at the foot or springing, but for a distance of 30 feet the coping was practically one solid continuous bar. A careful examination showed that the coping had “ grown” about a quarter of an inch longer than when it was first set, and that this ' Origin of Mountain Ranges, chap. iii. and iv. 2 T am indebted to Mr. F. Archer for first calling my attention to it. T. M. Reade—Effects of Temperature on Terra-Cotta. 27 lengthening, as shown by movement on the corbel bricks which occur at intervals, was evenly distributed along a length of 380 feet. One of the first explanations that occurred to me was that the lengthening was due to the expansion of the cement, as we know that cement if used too soon does expand for a certain length of time after setting! Enquiry from the builder, Mr. Bates, who put up the wall, showed this not to be a probable explanation, as the wall was built some seven years ago. Mr. Bates informed me that he reset the end bricks of this portion of the coping, about two years after the wall was built, in consequence of its lifting, and I have ascertained that Mr. Taylor, a bricklayer, has reset it on two occasions when it lifted from the same cause, first on May 9th, 1884, and secondly on May 16th, 1885. He has now just reset it for a third time. An inspection of brick copings in the neighbourhood of Blundell- sands, of which there are many, disclosed the fact that this is not a solitary phenomenon. In another case where the coping is of blue Staffordshire bricks, the top course in cement and the under-course in mortar, a change in length is shown clearly by the coping being lifted off the wall at each of the two ramps (curved changes of level) which exist in its length, and the movement can be clearly measured on the corbel bricks as before, and in this case the lengthen- ing is also a quarter of an inch, evenly distributed over a considerable length of coping. Numerous other examples are to be seen, which, though not so striking as those described, clearly evince a movement of the copings. It will no doubt be considered a long step from brick copings to mountain-building, but as a good example of the permanent lengthen- ing that may take place as the accumulated result of small movements of expansion by change of temperature in what appears to be an intractable material, the facts are well worthy of record. It appears that when the ends of a coping such as I have described butt up against a solid pier, this movement does not take place probably from the elasticity of the material being sufficient to absorb whatever small expansions may occur.” When one end is partially free to move, the effect is different, each expansion, however small, pushing the coping along towards the partially free end, and on contraction the coping cannot draw itself back to the same position as before, so must either fracture or lengthen by increments, and experience shows that is what frequently happens. 1 In order to ascertain precisely whether any alteration of length does take place in cement, I had a bar made composed of one of best Portland cement to one of fine sand. In this bar were fixed brass studs for measuring purposes. On Sept. Ist, three weeks after it was made, the bar measured 16°136 inches between the studs. On Noy. 6th it measured 16°122 inches, showing a shrinkage of 0:014 of an inch, and the contraction has not yet ceased. 2 Since this was written I have observed several cases in which the end brickwork and piers have been badly fractured by the force of expansion. 28 Alfred Beli—British Upper Tertiary Corals. ViI.—Britisa Uerrer Tertiary Corats. By Aurrep Brut. RITERS on Fossil Corals seem to ignore the existence of Corals in our later Tertiary formations. They are certainly not common. The following reference and species have come under my notice: Caryophyllia clavus, Scacchi var. borealis, Flem., Lancashire drift (see Geologist, 1845, p. 124). Caryophyllia clavus var. Smithit, Stokes, Raised beach, Portrush, Co. Antrim (Portlock, Geol. London- derry, etc.). Sphenotrochus Wrightii, Gosse, from the Clyde beds, by Messrs. Crosskey and Robertson. To these I may add a fine calice of the Norway branching Coral Lophohelia prolifera, Ed. and H., from the interglacial sands of King Edward, N.B., and a single young example of Sphenotrochus Macandrewanus, EH. and H., from the Raised sea-bed, Largo Bay, Fife. T'wo species occurring in the disturbed portion of the Suffolk Red Crag appear to be of Diestien origin, viz. Solenastrea Prestwichit, Dune., present in beds of that age in Belgium (Brussels Museum), and a stout form of Flabellum, whose affinities are rather to F. appendiculatus, Nyst, than to F. Woodii of the Coralline Crag, to which it is commonly referred. I judge this after an examination of a large number of specimens of the different species— mostly worn and rolled examples. The “ Reed Coll.,” York Museum, contains a minute Sphenotrochus not more than 4; inch in height, which I obtained from the well- known Chillesford Sands at Aldeby. I have only seen this one example, and have, pending further discoveries, given it the trivial name of S. parva. The Crag Sphenotrochi would probably repay further examination, as in several instances I have noticed that the costez instead of presenting the usual strait parallel arrangement, sometimes wavy at the lower end, are strongly wavy, the projections interlocking one within the other P.S.—Since writing the above Mr. Tomes, F.G.S., has kindly examined the corals referred to in the last paragraph, and describes them as follows :— SpHENoTRocHUS BoyTonEnsts, Tomes, n.s. The corallum is of equal breadth for the whole of its height, but it is very thin at the base. The curve of the margin of the calice in the long direction is about the same as in Sphenotrochus intermedius. The long diameter of the calice to the short one is as 6 to 4. There are twenty-four septa and the primary and secondary ones are united to the columella by trabicule, which are not in pairs, but are single. A few large papilla appear on the sides of the septa, which have also horizontal ridges ending in simple blunt teeth on their inner margin. These with the growth of the corallum are elongated inwards and become trabicule, and are attached to the columella. The latter part as in Sphenotrochus intermedius is notched in the middle. The costez are very uniform in size over the whole of the Notices of Memoirs—Dr. H. Hicks—Pre-Glacial Man. 29 corallum, and they are all strongly crispate’ on every part of it. Height of the corallum 7 lines; greater diameter of the calice, 3 lines, its smaller diameter 2 lines. The greater size of this species, its remarkable costs, and the ridges on the sides of the septa will distinguish it. In the nature of the coste, though in no other respect, it bears some resemblance to Sphenotrochus crispus. The ridges across the septa ending internally in trabicule are very peculiar, andl give to the latter a oreater degree of importance than they would otherwise have. Localities.—Coralline Crag, Oxfords Red Crag, Boyton, Suffolk ; Walton-on-the-Naze, Essex. IN @ Fk ieo SOs eV VE @ ase S- T.—On roe Micrations or Pre-GuactaL Man. By Henry Hicks, IMSS HRs SestHi: Gra9:7 EFERRING to the further researches carried on, this summer, at Cae Gwyn Cave, North Wales, which is 400 feet above sea-level, the author stated that the additional evidence obtained proved most conclusively that the flint implement found there last year in association with the remains of Pleistocene animals was under entirely undisturbed Glacial deposits. He maintained also that the evidence is equally clear in regard to the implements found within the caverns, which he said must have been introduced before marine action disturbed the contents of the caverns and the Glacial deposits blocked up and_ covered them over. The question as to the direction from which pre- Glacial man reached this country is an exceedingly interesting one, and seems now to be fairly open to discussion. It is admitted to be fraught with difficulties, but the facts recently obtained seem to require that an attempt should be made to unravel it. The evidence, so far as it goes, points to a migration to this country from some northern source, as the human relics found in the caverns, and also in the older river gravels (which Prof. Prestwich is now disposed to assign also to the early part of the Glacial epoch, when the ice- sheet was advancing), occur in association with the remains of animals of northern origin, such as the Mammoth, Rhinoceros, and Reindeer. Up to the present no human relics have been found in this country (and it is very doubtful whether they have been found in any other part of Europe) in deposits older than those containing the remains of these northern animals. If man arrived in this country from some eastern area, it is but natural to think that he would have arrived when the genial Pliocene climate tempted numerous species of Deer of southern origin, and other animals suitable as food for man, to roam about in the South-east of England. 1 T borrow this descriptive word from MM. Milne Edwards and Haime, but it would be almost better to say that they are zigzag or serpentine. » Abstract of Paper read in the Anthropolog ‘ical Section of Brit. Assoc. Manchester. 30 Notices of Memoirs—Law and Horsfall—Carboniferous Fossils. Hitherto, however, not a relic has been found to show that man had arrived in this country at that time. But in the immediately succeeding period, with the advent of cold conditions and of the northern animals, evidences of his presence become abundant. Whether man at an earlier period migrated northward from some tropical or sub-tropical area, where he could have lived on fruit and such like food, there is no evidence at present to show ; but it seems certain that the man of the Glacial period in this country lived mainly on animal food, and that he found the Reindeer to be the most suitable to supply his wants. He followed the Reindeer in their compulsory migrations, during the gradually increasing Glacial con- ditions, and kept mainly with them near the edge of the advancing ice. IJ.—On tHe Discovery or CarponiFerous Fosstrs 1n A Con- GLOMERATE AT MoucutTon Fenn, NEAR SetTTiE, YORKSHIRE. By Rosert Law, F.G.S., and James Horsratt.! FTER briefly noting the various exposures of the conglomerate, its unconformability with the Silurian rocks, its nature, probable age, and the circumstances which led to the discovery of fossils in it; the authors described the following section exhibited on the south-west side of Moughton Fell. a. Scar Limestone, of light grey colour and well jointed; layers very distinct in lower parts and almost horizontal, the genus Bellerophon being the com- monest fossil in the lowest bed of this rock. Thickness from 300 to 500 feet. 6. ConcLtomERATE.—Of a bluish-grey colour when newly fractured, and becoming reddish on exposure to the air. The fragments are rounded, angular, and sub-angular in form, consisting of slate, grit, flagstone, and vein-quartz, all apparently derived from Silurian rocks. Fossil shells and corals are common throughout the bed. Bellerophon, Euomphalus, Syringopora and Lithostrotion are the prevailing genera. Thickness from 1 to 12 feet. c. Lower Silurian slates, of great thickness, having a N.E. strike and a dip of about 65°. The dip and cleavage appear to be on the same plane in this locality. The nature and the origin of the stones in the conglomerate were next pointed out; also it was shown that the portion of the bed in which fossils had been found was not more than 200 yards in length, and that it was thickest in the middle, thinning out to the east and west, and at one point could be seen merging into the overlying limestone. The fossils collected from the conglomerate are as follows :— Syringopora ramulosa. Bellerophon cornu-arietis. Lithostrotion basaltiforme. Natica plicistria. Euomphalus pentangulatus. Natica lirata. Cirrus, one species. Natica elliptica. Sanguinolaria angustata. Inoceramus, one species. Pleurotomaria, one species. Spirifera, one species. Orthoceratite, one species. Pecten, one species. Rhynchonella acuminata. Productus, three species. Bellerophon tangentialis. Leptaena, one species. In conclusion, attention was called to the probable method by which the conglomerate was formed. 1 Abstract of paper read before the Geological Section of British Association, Manchester, 1887. Reviews—Memoirs Geological Survey—East Lincolnshire. 31 Jey) da Wh db dah Wwe Se I. —Memorrs or THE GeEotogicaL Survey. Ene@nuanp anp WALES. Tue Geotocy or Parr or Hasr Lincoimnsuire. By A. J. JuKES-Browne, F.G.S. 8vo. pp. 181, with 25 Woodcuts and a Plate of Sections and Map. (London, 1887.) HIS memoir treats of the geology of the country near the towns of Louth, Alford, and Spilsby, and is the official Explanation of Sheet No. 84 of the Geological Survey Map of Great Britain. In a concise introductory note the Director-General tells us that the district of which the geology is here described is the southern half of the Wolds, north of the Wash; and that the Memoir gives (1), a detailed account of the various Formations from the Kimeridge Clay to the top of the Middle Chalk. (2.) The subdivisions estab- lished by Professor Judd among the Lower Cretaceous (Neocomian) rocks of Lincolnshire have been adopted by the Geological Survey, as well as his name of “ Tealby Beds” for the Middle Division of that series. The name of ‘Spilsby Sandstone” is proposed for the Lower Division. The Upper Group, or “ Carstone,” here generally consists of mere loose sand. The several subdivisions of the Chalk in this region are now for the first time compared with those which have been worked out by the Survey in Buckinghamshire and Cambridgeshire. (8). A full description is likewise given of the Glacial Deposits which occupy the lower grounds flanking the Wolds ; but for his theoretical views, which are not always in accord with those of his colleagues, the author of the Memoir is himself respon- sible. In connexion with the superficial deposits, he has discussed the comparative age of the several valley-systems of the district. (4). Among the facts of economic importance described in the Memoir is the discovery of two horizons of ironstone and also a seam of phosphatic nodules. (5). A large number of well-sections bear- ing on the subject of Water-supply are given in the Appendix. A general description of the geological structure and the physical characters of the district is first given, with lists of the heights, and some sections (pp. 1-8). The Kimeridge Clay is then described (pp. 9-12). The so-called Neocomian Series (pp. 13-27) begins with a nodule-bed on the Kimeridge Clay and at the base of the Spilsby Sandstones, which latter alone the author refers to the Neocomian of the Continent, whilst others make it the lower part of that series. The nodules consist largely of rolled fossils, difficult to determine, but for the most part derived from older beds, probably Kimeridgian (p. 18), but possibly Neocomian (p. 139). The sandstone has large calcareous, fossiliferous concretions in it ; and the fossils comprise both Oolitic and Neocomian forms, indicating an intermediate stage between the two systems (p. 141). Then follows the variable Hundleby Ironstone, equivalent to that at Claxby, and forming the base of the Tealby Clay. This iron- stone is a ferruginous loam with oolitic grains of iron-oxide; and the facies of its fossils ‘is characteristically Neocomian” (p. 141). The “Tealby Beds” are (1) the ironstone above mentioned; (2) 32 Reviews—Dr. Marsson’s Chalk Bryozoa of Rugen. clays with thin sandstones, septarian nodules, selenite, and pyrites ; (3) the “roach,” a ferruginous marl with oolitic grains. The clays and the nodules near their base give fossils of an “ eminently Neocomian” character. The sands representing the ‘“ Carstone,” or Upper Neocomian of the district (pp. 28-27), have few fossils, but many phosphatic nodules. The Upper Cretaceous of Lincolnshire (pp. 28-70) consists of the Lower Chalk and the Middle Chalk; and this begins with (1) the Red Chalk (overlying the Carstone Sands); and this is succeeded by (2) the ‘ Inoceramus-beds,” (3) the “zone of Holaster sub- globosus,” and (4) a ‘“shaly marl.” Next above comes (5) “hard rocky chalk,” making the base of the Middle Chalk, followed by (6) ‘*Chalk with flints and Inoceramus Brongniarti.” In Cambridge- shire the equivalents of these divisions are—for part of 1, 2, and part of 8, the ‘*Chalk-marl,” or “zone of Rhynchonella Martini” ; for part of 3, the ‘‘ Totternhoe Stone”’; for the rest of 8 and 4, a similar zone and shaly marl; for 5, the “Melbourn Rock” and the “gone of Rhynchonella Cuvieri” ; for 6, the “zone of Terebratulina gracilis,” which is succeeded by the “zone of “olaster planus,” and then by the ‘ Chalk-rock,” neither of which members of the Middle Chalk appear in Lincolnshire (p. 80 and footnote). The relative value of ‘these divisions is discussed; the details of their thick- nesses, characteristics, and chemical constitution, and paleontology are carefully explained, as well as their sections, exposures, and surface-features. Six woodcuts and several tables illustrate this chapter; and the fossils are tabulated and noted at pp. 142-147. The Glacial Deposits (pp. 71-101, with woodcut sections, figs. 11 to 19) are described in detail as the “Older” and the ‘“ Newer Boulder-clay ;” and the Post-glacial Deposits (pp. 102-112), as (1) the “ Revesby Gravel’’; (2) the. Marsh and Fen Deposits ; and (3) Blown sand. All of much interest, both locally and generally. Chapter IX. (pp. 118-131), treating of the hills and valleys of the Wolds, is an explanation of the physical features of Hast iLéngollneti, worked out con amore, carefully written, and well illustrated with plans and sections. Amateurs as well as specialists must derive a real scientific pleasure in following Nature’s pro- gressive handiwork in rendering this part of the Hast of England what it now is. The Economics and Water-supply are very well calculated to serve the country. A useful Index and good plate of sections complete this valuable Memoir. II.— Die BryozoEN DER WEISSEN SCHREIBKREIDE DER InseL RUGEN von TH. Marsson. Mit 10 T'afeln. Band 4, Heft 1, 1887. 4to. pp. 1-112. Palxontol. Abhandl. herausgegeben von Dames und Kayser. O Dr. Marsson of Greifswald paleontologists are already indebted for two beautifully illustrated memoirs on the Foraminifera,’ Cirripedia and Ostracoda of the White or Upper 1 Mittheil. des naturwiss. Ver. fiir Neuvorpommern u. Riigen in Greifswald, Zehnter Jahrgang, 1878, pp. 115-196, Tat. i.-y. Reviews—Dr. von Giimbel’s Geology of Bavaria. 30 Chalk of the Island of Rugen;! in the present memoir the Bryozoa of the same formation and locality are described in a similar careful and complete manner, and the new forms, as well as_ those imperfectly known before, are faithfully represented in the accom- panying ten plates, drawn from nature by the author’s hand. This group of organisms was included with others from Rugen in a memoir by von Hagenau* nearly fifty years since, but this author freely acknowledged the imperfect character of his work, which, however, he did not live to amend and complete. Dr. Marsson enumerates in the present memoir no fewer than 229 species, of which 84 belong to the Cyclostomata and 145 to the Cheilostomata. The following new genera are constituted, Crypto- glena, Epidictyon, Cavarinella, Rhipidopora, Clinopora, Crisidmonea, Stigmatocatros, Phormopora, Phormonotos, Phyllofrancia, Pithocella, Solenophragma, Bactrellaria, Coscinopleura, Columnotheca, Tcenio- porina, Bathystoma, Systenostoma, Platyglena, Nephropora, Lekytho- glena, Homalostega, Balantiostoma, Cryptostoma, Dioptropora, Kele- stoma, Lagodiopsis, Prosoporella, Pachydera, and Stichocados. Of the species enumerated 117 are peculiar to Rugen, and 96 of these are new forms, but it is probable that many of them will be subsequently discovered in other localities. It is certain, however, that a great many are limited to the Rugen Chalk, and no traces of them appear in the same formation of England or France. Four species extend down to the Neocomian, one to the Gault, 21 to the Cenomanian, and nine to the Turonian. With the Chalk of Maes- tricht there are 45 species in common. Only five species reach upwards to Tertiary strata, and one of these, Entalophora virgula, v. Hag., has survived to the present time, Mr. Waters stating that he can discover no differences between the fossil and existing forms. G. J. H. IIJ.—Geronociz von Bayern. Von Dr. R. Wituetm von GUmeet. Erster Tuern: Grunpztce per GeoLociz. LinreRUNGEN 1-5. Large 8vo. pp. 1087. (Kassel, 1884-7, Theodor Fischer ; London, Williams and Norgate.) aes the lately-issued fifth part, the first volume of the ‘Geology of Bavaria’ is completed ; it contains 1078 pages of printed matter and very numerous illustrations in the text ; thus forming a massive volume. ‘This first volume is entirely devoted to the “ Grundziige der Geologie,” and it has no special bearing on the ‘Geology of Bavaria,’ which is reserved for the second volume. It forms a very comprehensive and complete Manual or Handbook to Science, and may fairly claim a position equal to that held by our English Text Book of Geology by Dr. Geikie, and by Lapparent’s Traité de Géologie in France. The subject is treated under three heads: (I.) Hylology of the Earth; (11.) Formation of the Earth, or Geotektoriek; and (III.) Geogeny, or the History of the EHarth’s Development. Under the 1 id. 12 Jahrg. 1880, pp. 1-50, Taf. i-iii. * Monogr. der Riigens’chen Kreide-Verst. 1839. DECADE III.—VOL. V.—NO. I. 3 34 Reviews—Daubrée’s Subterranean Waters. first heading is comprised a very full description of the mineralogical and petrographical constituents of the Earth’s crust, and their micro- scopical characters are particularly well illustrated. This is followed by a section on the Morphology of the rocks and of the Crust of the Earth formed by them, and their origin and formation are treated in another section. A general review of the different organisms occurring as fossils is also included in the Hylology, and figures are given of the principal representatives of each group. Under the second heading of the Formation of the Harth, the Archeolithic, Paleeolithic, Mesolithic, Keenolithic, Post-tertiary and Novir or Recent Groups are described, and their mode of occurrence and development in different parts of the Earth are fully referred to. Figures are given of the most typical sections in various countries and of the leading fossils of each group. In the third division of Geogeny or history of the Harth’s development, the relations of the Harth to the universe and to the solar system are considered, as well as its individual character as a planetary body. In the concluding sentence of this division and of the book the author states, that if from a geological standpoint we may draw a conclusion as to the future of the Earth from its past history, we may look forward to an almost unending period, as measured by human standard, of still higher development, and in the furthest distance there is the probabality of a gradual and finally complete refrigeration and the exhaustion of its waters. G. J. H. 1V.—Les Eaux Sourrrraines 4 L’ Epoque ACTUELLE; LEUR REGIME, LEUR TEMPERATURE, LEUR COMPOSITION AU POINT DE VUE DU ROLE QUI LEUR REVIENT DANS L’ECONOMIE DE L’ECORCE TERRESTRE. Par A. Dausriz, Membre de I’Institut, etc., ete. Two vols. pp. 767, with numerous illustrations. (Vve. Ch. Dunod, Kditeur, Paris, 1887.) HIS important work bears about the same relation to “Les Eaux Souterraines aux Epoques Anciennes,” reviewed in our last Number, as the “ Principles of Geology ” does to the ‘‘ Elements,” inasmuch as it treats of causes now in operation. The author, from the position occupied by him, has had great opportunities for acquiring information on this most extensive subject from all quarters of the world, and the work conseqnently is the result, in part, of his own large experiences, and partly a selection from the information afforded by other writers. The first book, which is also the largest and most important, contains seven chapters devoted to the consideration of the phenomena in connection with the system (régime) of underground waters. He commences with an allusion to quarry-water, giving an extract from the results of M. Delesse of the weight of quarry-water per hundred of the wet mass, ranging from 20:66 in white chalk to 0-08 in vein-quartz. In a previous review of Mons. Daubrée’s great work (Ktudes synthétiques de Géologie expérimentale) mention was made of the important part which this same quarry-water plays in the economy of the Harth’s crust, and of the interesting experiments Reviews—Daubrée’s Subterranean Waters. 30 of the author by way of showing how it can make its way against a powerful pressure of steam. This has an important effect in the general mechanism of infiltration (vol. ii. p. 214), and helps to over- come the obvious difficulty with respect to water circulating in open fissures, which would appear liable to be forced back by pressure from within. After giving a description of the permeable and impermeable rocks, the author discusses the phenomena in connection with the more superficial sheets of water, such as have no impermeable bed above them. Having rather a partiality for Greek compounds, he designates this ‘ Phreatic Water.” The water-line, or upper level of this sheet, ranges from a few feet to 100 métres or more. This « Phreatic,” or well-water, is largely distributed throughout Drift beds (Terrains de transport), and many plans and sections are given showing its “régime” in different towns of Europe. He quotes from Prestwich’s address to the Geological Society (1872) with reference to the water-bearing gravels of London which repose on an impermeable clay, and relates how that, before the great water companies furnished an independent supply, the metropolitan popula- tion was largely confined to the water-bearing gravels. Curiously enough, in order to illustrate this, a section is given of the aquiferous gravels at Oxford resting on the Oxford Clay. Not the least interest- ing account of the superficial sheet of underground water is that relating to the Fontanili of Lombardy, illustrated as usual by small plans and sections. The inhabitants of the favoured district are in the habit of knocking out the bottom of a tall cask, and placing it in an aquiferous bed, some two or three metres below the surface, when the pressure raises the water in the shaft or funnel thus formed, and a notch being cut in the upper rim, the surplus water is thus con- ducted into channels of irrigation, much on the principle of water meadows in the South of England. The water-bearing strata of Lombardy above referred to occur in the gravels and sands of old and modern alluvions, and the water which they contain percolates towards the great rivers to such an extent as to restore to these the water of which the numerous irrigation canals had deprived them. The “ Phreatic Water” is by no means confined to the Drift, as of course beds of Tertiary, Cretaceous, Jurassic age, etc., contribute their quota when these occupy the surface of a country. Under this heading some interesting details are given of the well-water of Paris, which, it appears, is contained partly in the alluvium and partly in permeable Tertiary beds upheld by the Plastic Clay. Since M. Daubrée has so extremely enriched his work with plans, sections, photographs, ete., a section across the valley of the Seine at Paris in illustration of these interesting details would have helped the reader, who is not a little puzzled to find a plan apparently of the alluvial deposits near Paris immediately under the heading “terrains tertiaires des départements de la Seine, etc.” The results of contact between permeable and impermeable rocks are next discussed. The contact may be the result of simple strati- fication, as when sands or gravels overlie clay. The section at 36 Reviews—Daubrée’s Subterranean Waters. Oxford, after Prestwich, which had already appeared on page 42, vol. i. a propos of the “ Phreatic Water,” is again introduced at p. 73, but it is difficult to say that it illustrates any ‘thing very special. Numerous other sections are given in illustration of the subject. Contact by accidents posterior to the stratification is next considered ; such as the accumulation of water in decomposed granite or growan, the granite itself being of an impermeable nature. Then, again, there are the phenomena presented by slips or talus, such as that shown at the source of the Creux-du-vent, where the spring has been dis- placed by a great slip on the flanks of a precipice of Jurassic rock (p. 98, vol.i.). There are also great accumulations of water in porous volcanic ejectamenta, which are thrown out in contact with more compact rocks. Some curious instances in Central France are given with plans and pictorial illustrations. Faults, of course, are well known to produce springs by bringing sandstones, limestones, etc., against clays. Such an one occurs in the neighbourhood of Loudun, where Mesozoic beds are represented (section, vol. 1. p. 111) as being traversed by a fault of considerable throw, which is vertical or even slightly reversed. The most important chapter in the book is entitled “Role des lithoclases de divers ordres.” M. Daubrée has a partiality for sub- division ; and, as we have already seen, for Greek compounds. He had previously given us some interesting phenomena in connection with faults (failles), but much the same things now figure under the far grander title of “paraclases.” Joints he calls ‘“ diaclases ” ; whilst another class of fractures, many exceedingly minute, he calls “ Jeptoclases.” To a subdivision of this latter, called “synclases,” he refers those fractures due to contraction. The whole are summarized under the general term “ lithoclases.” The upshot of all this is, that rocks are fractured in various ways, by various agencies and in different degrees, and of course such fissures facilitate the accumulation and circulation of underground waters. Under the general heading of “lithoclases” he appears to include the artificial piercing of rocks and artesian borings. Mons. Daubrée has now fairly settled down to his work (Role des lithoclases), and once more takes us through the formations in suc- cession, no longer dealing with the mere top-water (Phreatic) of ordinary wells, however deep, but showing us the mechanism of underground waters in its more complex phases. Considered as a whole the Paris basin is eminently suitable for the making of artesian wells. The beds there are disposed in the form of bowls of de- creasing size placed one within the other, the position of Paris itself being almost central with regard to them. These formations, alternately permeable and impermeable, are very slightly disturbed ; many levels furnish hundreds of artesian wells, whose depth varies habitually from 10 to 80 metres. For further particulars he refers to the “Guide du sondeur” by Degousée and Laurent. These remarks refer to the Tertiaries. and under the same heading he gives us an interesting account of artesian borings in the Sahara of Touggourt, to the south of Biskra. The first artesian wells of this Reviews—Daubrée’s Subterranean Waters. Bi region (the Oued-Rhir) are very ancient, and there are reasons for supposing that the employment of this method of obtaining water was older than the Arab conquest of the country. He then enumerates and partly illustrates by plan and section, as many as five distinct artesian basins, in a traverse from south to north through the Province of Constantine, corrresponding to the undulations of the Quater- nary (?) beds of the Sahara. Under the heading ‘terrains crétacés” important plans and sections are given of localities in France. Not the least interesting are the phenomena in the Department of the Aube, where the waters percolating the porous Upper Chalk are thrown out by the lower ‘marls. It is thus that the base of the chalk cliff is marked by numerous springs, some of them powerful enough to turn mills; amongst these is the source of the Vanne beneath the viilage of Fontvannes, which affords a supply of water to Paris itself. The spring of la Folletiére in the Calvados boiling up from the glauconitic chalk is pictorially represented. But the most important of all under the heading “ Cretaceous” is the account given of the artesian borings at Paris itself, which, as previously observed, is in the centre of one of the most perfect basins perhaps to be found anywhere. The boring at Grenelle, which occupied seven years, after traversing some 50 métres of Tertiary beds and the whole of the White and Grey Chalk, attained a depth of 547 métres, when water was found abundantly in the Greensand. A section of this pioneer deep-boring, drawn to scale, together with certain well- known buildings of Paris for comparison, will be found on page 210, vol.i. Many interesting details of subsequent borings are also given. Dealing with the English Cretaceous, Mons. Daubrée reproduces some of the sections of Mr. Lucas with respect to the North Downs, and of Mr. Robert Mortimer with respect to the Chalk Wolds of Yorkshire. From the latter writer many interesting facts connected with this subject are abstracted; but a portion of these is unfor- tunately placed under the heading “Oxfordshire and Whitshire,” betraying an indifference to British geography of which we have a further example (p. 351, vol.i.), where the author seems to fancy that the Swailow-holes of Ingleborough and Castleton are in the neigh- bourhood of Bristol! Still dealing with the Cretaceous, he adduces many important instances in relation to springs, etc., more or less illustrated by plans and sections, from the north of France, Belgium, Westphalia, etc., touches very briefly upon Ireland, and concludes by reproducing some very elaborate sections by M. Dru relative to the Caucasus. The beds of Jurassic age, as M. Daubrée remarks, with their fissured limestones and stiff marls or clays, are eminently calculated to produce springs. Many interesting cases are quoted, and amongst others he reproduces a section through Rutland by Prof. Judd, which is intended to show two separate water-lines, one at the junction of — the Inferior Oolite and Upper Lias, the other at the junction of the Marlstone-rock with the clays of the Middle Lias. We may here take the opportunity of observing that few places in England present 38 Reviews—Daubrée’s Subterranean Waters. such a number of boiling springs, or river-heads, as does the Vale of Pickering in East Yorkshire, where the porous and fissured Tabular Hills, composed mainly of Corallian rocks, sloping and dipping to the south, are underlain by Oxford Clay, and faulted against the Kimmeridge Clay, capped by Drift, forming the Vale itself. This region illustrates most admirably not only the “ Role des lithoclases,” but also the “‘ Réle du contact,” ete. After dealing with the Trias and Permian, the Paleozoic and Crystalline rocks, M. Daubrée concludes this important chapter by considering the phenomena in connection with metalliferous veins. But that these latter are discussed more fully in the companion work (Les eaux souterraines aux époques anciennes), the subject might seem to be treated somewhat briefly, since, from a geological point of view, there can be no more interesting theme than the connection between existing mineral springs and the associated deposits in the fissures through which such waters have passed. Instances are quoted from Plombiéres, Carlsbad, etc. ; in the latter case with ample illustration, the main point being to show that the hot springs of the region of the Sprudels occur at the intersection of two systems of fracture. The part played by caves in the system of underground waters is treated fully by the author; and since this division of the subject lends itself to pictorial illustration, there are several photographs of well-known sources. The fountain of Vaucluse is one so celebrated that Mons. Daubrée dwells at considerable length on its details as related by the MM. Bouviet. Truly a river of limpid water, full of trout and eels, issuing out of the hard and arid Urgonian limestone, it is just one of those spots which have given rise to all sorts of ingenious and even romantic speculations. It seems to be the sad mission of scientific inquiry to knock all these sort of notions on the head. Given a region of some hundreds of square kilométres of arid limestone without springs or wells, and at the same time seamed by dry ravines—if rain falls on such a desert in any quantity, a portion of this water must have an outlet somewhere. The con- ditions which determine the discharge are perhaps more complex than in the case of mere surface drainage. The remainder of Book I. is occupied with the consideration of the phenomena of water forced upwards by the pressure of its own or of other gases. The various sprudels and so-called mud volcanoes come under the latter denomination. Very interesting details are given of a boring at Montrond (Loire). The phenomena of geysers are then dealt with, not forgetting those of the Yellowstone Park, and of New Zealand. Before dealing with actual volcanoes, M. Daubrée introduces the subject of “soffionis,” i.e. jets of vapour endowed with a high temperature, which are projected from certain fractures of the ground. The best examples of this class occur in the boracic arid district of Tuscany, of which a tolerably full account is given, accompanied by many illustrations. According to the section (vol. i. p. 405), the country consists of Pliocene clays, Eocene lime- stone and shales, Cretaceous beds and Lias, all considerably plicated, Reviews—Daubrée’s Subterranean Waters. 39 and having a bed of serpentine interposed between the two Tertiary deposits. The pipes supplying the soffionis are represented as cutting across the several formations, but no suggestion as to their primary source is offered. With respect to volcanoes, M. Daubrée observes that in spite of the idea which they suggest generally of melted rocks originating in the dry way (voie ignée)), before all things they represent supplies of water, since everywhere the vapour of water is one of the principal products of their activity. An effective cnt of the explosion of Krakatau helps to illustrate this. Book II. supplies us with some valuable facts relative to the temperature both of cold and hot springs. Book III. deals with the composition of underground waters, First of all theauthorenumerates the substances dissolved or chemically deposited by them. Speaking generally, one may say that nearly all the elements or their primary compounds exist dissolved in water somewhere, either with or without the aid of other solvents; but sulphur, silica, and carbonate of lime are amongst the most abundant deposits. By way of illustration Mons. Daubrée gives a photograph of the mud springs with sulphur at Crater Hill after Hayden, and many other pictorial representations of silica and limestone deposits, taken from various quarters of the globe. Most of these are nowin full operation. Compounds of aluminium are rare; nevertheless the hydrous silicates of that mineral, such as allophane, are still being deposited. With respect to the classification of mineral waters Mons. Daubrée will not admit of any preconceived ideas: the predomi- nating substances must decide the grouping. The families are classified according to the principal electro-negative element, as chlorides, sulphides, sulphates, carbonates and silicates: the genera by the principal electro-positive (basic) element, as sodic, calcic, magnesic, ete. Under such an arrangement the waters of the Old Sulphur Well at Harrogate, which is a “strong saline sulphur” containing about 1000 grains of haloid salts to the gallon, would be classified as a brine, in spite of its free hydrogen sulphide and its five grains per gallon of sodium sulphydrate appealing alike to the taste and smell. At the same time it is not easy to say where Mons. Daubrée would draw the line, since he cites a spring at Baréges as a sulphur water which contains 0-04 grms. of sulphide of sodium to the litre out of 0-11 grms. of fixed substances, i.e. rather more than one-third. This is what would be called a “pure sulphur water ” in the language of the Harrogate doctors. The silicated waters (sources silicatées), as Mons. Daubrée justly observes, are of the highest interest to the geologist. The silica would usually seem to be in combination with soda, but weighable quantities of the silicates of lime, magnesia and alumina have been found in a water of the Hautes-Pyrénées. After glancing at the reactions of underground waters on the material bathed by them, the author proceeds to consider the origin of the substances dissolved in the water or chemically deposited by them. Amongst the most obvious are the filth of cities draining into rivers and contaminating the waters of shallow wells; then 40 Reports and Proceedings— there are rocks soluble in water, such as rock-salt and gypsum, and the carbonates, which require the aid of free carbonic acid in the waters, rocks whose decomposition produces soluble matter such as pyrites, ete., etc. Also water charged with saline matter probably possesses greater solvent powers over certain substances. The author then considers the principal elements and source of these compounds in succession in a tolerably long chapter. In a fourth book Mons. Daubrée makes some general observations relative to the subject, and especially discusses the origin of the temperature of underground waters. Again he illustrates the subject with numerous sections, showing from instances culled in all directions how the result may be influenced by plications of the strata at high angles, whereby the waters are drawn down through synclinal folds to depths where considerable elevation of temperature obtains. Even extinct volcanoes, and rocks of volcanic origin, such as basalts and trachytes, retain sufficient heat to influence the waters which percolate them. Asia Minor, for instance, is a country exceptionally rich in thermal springs. The subject of geysers and voleanoes is again resumed. With regard to the latter, Mons. Daubrée quotes Mr. W. L. Green, who bas studied the Hawaiian volcanoes, to the effect that in the eruptions of that archipelago the vapour of water has only played a secondary part. This is an important quotation in view of M. Daubrée’s previous assertions with respect to the functions of underground waters in these phenomena. It also bears upon a question which has of late much engaged the attention of Prof. Prestwich and other writers. Lastly, Mons. Daubrée discusses the part which water may play in earth- quakes. An index of subjects, a second of localities, and a third of anthors, accompanies the work, which, although having no special claim to originality, constitutes a valuable text-book on the question of under- ground waters, considered under almost every aspect which can well be conceived. For geological purposes it also affords a good intro- duction to the companion work already noticed, whici is likewise provided with copious indexes. W. H. H. Asal Ones) AID ey @ CASED Ness —$<——— GeroLocicaL Society or Lonpon. November 23, 1887.—Prof. J. W. Judd, F.R.S., President, in the chair.—The following communications were read :— 1. “Note on a New Wealden Iguanodont, and other Dinosaurs.” By R. Lydekker, Esq., B.A., F.G.S. The new species of Iguanodon was founded upon a left ilium and ischium, parts of the pubis and tibia, two metatarsals, several dorsal lumbar and caudal vertebree and other bones, obtained by Mr. C. Dawson, F.G.8., from the Wadhurst clay of the Hastings Sand. The species now described, which was named after the discoverer, Geological Society of London. 4] and TIyuanodon Prestwichi, were shown to form a peculiar and aberrant group of the genus Iguanodon. A maxilla from the Wealden of the Isle of Wight was also described and referred to Ornithopsis. The recent examination by the author of the remains of Dino- sauria in the British Museum for the purpose of preparing a catalogue, had enabled him to make several notes on the various forms represented in the collection, and these notes were embodied in the present paper. The principal subjects mentioned were the following :—The identification of Iguanodon Seeleyi with I. bernis- sartensis; the genera Sphenospondylus and Cumnoria of Prof. Seeley ; a British species of Trachodon from the Cambridge Greensand ; an ilium, provisionally referred to Hylgosaurus, from Cuckfield ; the genera Vectisaurus and Regnosaurus; the relations of the Sauro- poda and Theropoda; the type specimen of Ornithopsis Hulket ; the similarity of the humerus in Pelorosaurus and Brontosaurus ; the vertebrae and other remains of Cetiosaurus brevis; the humerus of C. humerocristatus and its relations to Ischyrosaurus, Hulke, Giganto- saurus, Seeley, and Ornithopsis Leedsii, Hulke; the affinities between Cetiosaurus oxoniensis and Morosaurus; the occurrence of Titano- saurus in the Wealden of England and the possible identification of that genus with the Dinodocus of Owen; the vertebrae described by Owen as Bothriospondylus magnus; the types of the genera Theco- spondylus and Bothriospondylus ; and some Megalosaurian teeth. 2. “On the Cae-Gwyn Cave.” By T. McKenny Hughes, M.A., F.G.S., Woodwardian Professor of Geology, Cambridge. The subject fell into two divisions: The Age of the Drift outside the Cave, and The relation of the deposits in the Cave to that Drift. The author contended that the drift outside the cave was a marine deposit remanié from older beds of glacial age, but was itself post- glacial and of approximately the same date as the St. Asaph drift ; in confirmation of which he gave the following list of shells from that drift outside the cave:—Ostrea edulis, Pecten varius, Mytilus edulis, Cardium echinatum, C. edule, Cyprina islandica, Astarte borealis, A. suleata, A. var., Venus gallina, Tellina balthica, Psam- mobia ferroensis, Mya truncata, Fissurella greca, Littorina littorea, Turritella terebra, and Buccinum undatum; pointing out that there was only the one species of Astarte among them which was not common on the adjoining coast, just as there were in the older post- glacial river-gravels of the 8.H. of England two locally extinct forms, the Corbicula fluminalis and the Unio littoralis, and discussing various difficulties, stratigraphical and paleontological, in the way of accepting the view that the cave-deposits were glacial, inter- glacial, or preglacial. For instance, he remarked that there were no marks of glaciation on the face of the rock in which the cave occurred; that the cave-deposits were like drift because derived from it, but that no continuity existed between the drift and the cave-deposits; that there was a much greater thickness of rain-wash and resorted marine-drift looped down over the upper opening into the cave than over the adjoining surface. The upper part of this 42 Reports and Proceedings— resorted drift is exactly similar to the material which had accumu- lated against the old fence, the very existence of which had been denied. The swallow-hole action to which he referred the pheno- mena was proved by the opened fissures and vertical cylindrical holes in the limestone and by the occurrence of a land-shell (Zonites cellarius). He held that there had been a breakdown of the roof and wall of the cave under the drift, and that angular masses of limestone, due to this cause, were found all along in front of the upper opening to the cave. No bones were found outside that barrier, there being no bones in the shell-bed and no shells in the bone-bed except the land-shell washed down through a fissure. Instead, therefore, of the difficult task of proving that there were in the district many well-known processes connected with subter- ranean denudations, which might explain the superposition of the marine drift upon the bone-earth, each of which had played a part in producing the results observed, he maintained that we had now the clearest evidence as to the exact manner in which it was all brought about, namely, that the marine drift was deposited before the occupation of the cave by the animals whose remains have been found in it; that at the time of the occupation of the cave the upper opening now seen did not exist, but the animals got in by the other entrance; that against the wall of the cave where it approached most nearly to the face of the cliff, the drift lay thick as we now see it; that by swallow-hole action the cave was first partially filled, and then the thinnest portion of its wall gave way gradually, burying the bone-earth below it, and letting down some of the drift above it, so that some of it now looks as if it might have been laid down by the sea upon preexisting cave-deposits. II.—December 7, 1887.—Prof. J. W. Judd, F.R.S., President, in the chair.—The following communications were read :— 1. “A Letter from H.M. Secretary of State for the Colonies, en- closing an account of recent Discoveries of Gold in the Transvaal.” The deposits in which gold has been found, locally known as “ banket,” consist of a quartz-conglomerate forming so-called * reefs,” which traverse the veldt paralled to, but at a short distance from the rocky ridge of Witwatersrand. These masses always dip to the south, but at angles varying from 50° up to 90°. The “reefs” are believed to have been discovered by Mr. Struben, an English gentle- man long resident in the country. The “main reef” has been traced for twenty-five or thirty miles, and varies in breadth from 5 feet 6 inches to 15 feet; parallel and branching “reefs” of smaller dimensions have also been found. The yield of gold is said to be very variable in different portions of the “reef,” different samples with from 8 0z. to 4.0z. per ton occurring in close proximity. So far as observation has gone (and the deepest workings have only reached a depth of from 70 to 150 feet), the yield of gold has gene- rally increased as the reefs are followed downwards. 2. “On the Age of the Altered Limestone of Strath, Skye.” By Dr. Archibald Geikie, F.R.S., V.P.G.S. Geological Society of London. 43 The remarkable alteration of the limestone of Strath into a white saccharoid marble, first described by Maculloch, has hitherto been regarded as an instance of contact-metamorphism in a rock of Liassic age. The various writers who have described the geology of the district have followed Macculloch in classing the whole of the ordinary and altered limestone with the Secondary series of the Inner Hebrides. The author, however, saw reason in 1861 to suspect that some part of the limestone must be of the age of the Durness Lime- stone of Sutherland, that is, Lower Silurian; and he expressed this suspicion in a joint paper by the late Sir R. I. Murchison and him- self, published in the 18th volume of the Quarterly Journal of the Society. He has recently returned to the subject, and now offers lithological, stratigraphical, and paleontological evidence that the altered limestone is not Lias, but Lower Silurian. In lithological characters the limestone, where not immediately affected by the intrusion of the eruptive rocks, closely resembles the well-known limestones of the west of Sutherland and Ross-shire. It is not more altered than Paleozoic limestones usually are. It con- tains abundant black chert-concretions and nodules, which project from the weathered surfaces of the rock exactly as they do at Durness. These cherts do not occur in any of the undoubted Lias limestones of the shore-sections. The limestone lies in beds, which, however, are not nearly so distinct as those of the Lias, and have none of the interstratifications of dark sandy shale so conspicuous in the true Liassic series. The stratigraphy of the altered limestone likewise marks it off from the Lias. There appears to be a lower group of dark limestones full of black cherts, and a higher group of white limestones with little or no chert, which may be compared with the two lower groups of the Durness Limestone. A further point of connexion between the rocks of the two localities is the occurrence of white quartzite in association with the limestone at several places in Strath, and of representatives of the well-known ‘fucoid beds” at Ord, in Sleat. These latter strata form a persistent band between the base of the limestone and the top of the quartzite, which may be traced all the way from the extreme north of Sutherland southward into Skye. Paleontological evidence confirms and completes the proof that the limestone is of Lower Silurian age. The author has obtained from the limestone of Ben Suardal, near Broadford, a number of fossils which are specifically identical with those in the Durness Limestone, and so closely resemble them in lithological aspect that the whole might be believed to have come from the same crag. Among the fossils are species of Cyclonema, Murchisonia, Maclurea, Orthoceras, and Piloceras. The relations of the limestones containing these fossils to the other rocks were traced by the author. He showed that the Lias rests upon the Silurian limestone with a strong unconformability, and contains at its base a coarse breccia or conglomerate, chiefly composed of pieces of Silurian limestone, with fragments of chert and quartzite. ~The metamorphism for which Strath has been so long noted is con- 44 Reports and Proceedings—Geological Society of London. fined to the Silurian limestone, and has been produced by the in- trusion of large bosses of granophyre (Macculloch’s “syenite’’) belonging to the younger, or Tertiary series of igneous rocks. 8. “On the Discovery of Trilobites in the Upper Green (Cambrian) Slates of the Penrhyn Quarry, Bethesda, near Bangor, North Wales.” By Dr. Henry Woodward, F.R.S., V.P.G.S. The absence in Wales of organisms in the Longmynd and Harlech group renders any discovery of fossils in beds of this early horizon of the utmost importance. A portion of a Trilobite (Palzopyge Ramsayi) and Annelide burrows had already been found; but Dr. Hicks, at St. Davids, has added a sponge, 2 Ostracods, 6 Trilobites, 2 Lingulelle, and 2 Thece (Agnostus, Plutonia, Paradoxides, Conocoryphe Lyelli, C. bufo, and Microdiscus sculptus). Dr. Hicks has pointed out the singular absence of organic remains in the Longmynds both in Shropshire, N. Wales, and Treland, and has urged the need of further explorations. As if in answer to this, the author has received from Prof. Dobbie an impression and counter- part of a Trilobite from Bethesda, near Bangor, about 34 in. long and 1# in. broad, also the head of a second specimen of the same species. These specimens were obtained from the Upper Green bed of the quarry, which immediately underlies the grits forming the brow of Bronllwyd and overlies the Purple Slate. The elabella i is marked by three oblique furrows on each side, the cheek-sutures are very obscure, and the eyes, which are minute (probably rudimentary), occupy the centre of the free cheek, the suture obliquely dividing the free cheek from the fixed. The outline of the head is rounded. There are fourteen free thoracic segments. The pygidium consists of about three coalesced somites. Comparing the Bangor fossil with Paradowzides, we find that Paradoxides has about twenty free segments. Asaphus, Ogygia, and Niobe have only eight thoracic rings, and the caudal shield is very large. Angelina agrees with the Bethesda specimen in the number of its free segments; but the glabella is smooth, the pleure are broader, and the cheek-spines very long. Olenus has fourteen rings ; the glabella is furrowed, but the head- shield is shorter and broader, and ‘the ends of the pleuree and margin of the caudal shield are usually produced into spines. Olenus is also smaller. Conocoryphe has fourteen free segments; the axis is parallel-sided, and does not diminish backward from the head to the pygidium ; each ring of the axis is notched on its posterior border, and the ends of the pleuree are rounded ; the glabella is furrowed obliquely ; the eyes are often wanting or are minute. From these considerations the author concludes the Bangor fossil to be referable to Conocoryphe, and to a new species, C. viola. The Trilobite was found by Robert E. Jones and Robert Lloyd, two quarrymen, at Bethesda. Afterwards Prof. Dobbie found a detached head of the same species near the spot where the original Correspondence—Prof. H. G. Seeley. 45 specimen was obtained. The author desires to return thanks to Prof. J. Dobbie, of the University College of North Wales, Bangor, for the opportunity of describing these specimens. 4. “On Thecospondylus Daviesi, Seeley, with some Remarks on the Classification of the Dinosauria.” By Prof. H. G. Seeley, F.R.S., E.G.S. The author described the anterior third of a vertebra from the Wealden, which was recognized by Mr. Davies as the cervical vertebra of an animal allied to the genus Celurus, Marsh. The only Huropean genus hitherto described in which the vertebrae are similarly elongated, compressed, and enveloped in a dense external film of bone is that indicated by the sacrum, named Thecospondylus Horneri, whose vertebre are about 11 centimetres long, whilst the cervical vertebrae now under discussion were 9 centimetres long when complete. The specimen has lost the prezygapophyses and cervical ribs. If these were restored, they would probably approxi- mate in shape to those of Celurus fragilis. The author gave an outline-restoration. The points of resemblance were chiefly the elongated form, lateral compression of centrum and neural arch, inclined articular face of centrum, mode of attachment of the ribs, the convex external surface of the neural arch, almost total suppression of the neural spine, and the thin texture of the bone. But this affinity does not amount to generic identity, and he indicates the points of difference. In estimating the resemblance to Thecospondylus he regards the thinness of the investing layer of bone, the smoothness of its internal surface, and the elongation and lateral compression of the vertebrae, and a certain general approxi- mation in form; the most remarkable difference is the absence from the cast of Thecospondylus Horneri of indications of films of bone, or evidence of internal plates, such as are seen in the present specimen. He observed that Prof. Marsh regards Celurus fragilis as a generalized Sauropsid, with more resemblance to Dinosaurs than to Pterodactyles. Professor Marsh has formed an Order, Sanropoda, which includes Cetiosaurus and Ornithopsis. The author remarks that he had already suggested Cetiosauria as separable from the rest of the Dinosaurs. When an additional Order is instituted for animals with cavernous or pneumatic vertebrae, the Theropoda of Marsh, under which Celurus is grouped, it becomes necessary, in order to determine the systematic position of Thecospondylus, to review its relations. The author would unite Sauropoda with Theropoda into one Order, the Saurischia, whose pneumatic skeleton is an approximation towards Ornithosaurs and Birds. CORRESPONDENCE. —— CLASSIFICATION OF THE DINOSAURIA. Srr,—Will you allow me to state that I did not forward to the _GeotoctcaL MaGazine the abstracts of my British Association papers printed in the December Number, pp. 561-563, and that no proof of those abstracts was submitted to me; so that I am not responsible 46 Correspondence—Prof. T. G. Bonney—Mr. A. Somervail. for the publication. In the paper on the classification of the Dino- sauria, I do not adopt the names given on p. 562; but use the name Ornithischia for the order of which Omosaurus is an example, there named Omosauria ; while the name Sauwrischia is used for the order comprising allies of Cetiosaurus, there named Cetiosauria. I shall be glad if this erratum is corrected on p. 562, so that the names which appear there may not be quoted, and may be considered not to have been published. Tue Vine, SEVENOAKS, Dec. 3, 1887. H. G. SEELry. DIMETIAN OF ST. DAVIDS. Srr,—Mr. Mellard Reade in his paper ‘‘On the Dimetian of St. Davids” does not state whether the rock which he found included in the “ Dimetian,” and which he calls a “ green shale,” has been proved to be such by microscopic examination. Will he kindly supply the omission; because, without such an assurance, his proof of the intrusive character of the “ Dimetian”’ has no more validity than an arch without a keystone. T. G. Bonney. PROF. BONNEY ON BANDED GNEISSES AND THE METAMORPHIC ROCKS OF SOUTH DEVON. Str,—Would you kindly allow me space for reply to Professor Bonney’s letter in your issue for December, on the above subjects, more especially the latter, which directly affects myself. This portion of his letter forms a marked contrast to the other, and at the outset I beg to protest against its style and tone, which I shall not -condescend to imitate in this reply. It is possible or even probable that I may be wrong in my interpretation of these South Devon rocks, and if so, on further and better proof I shall be as happy in the opposite conclusion, as I earnestly trust that I follow science or truth for its own sake. With regard to the use of the microscope in geology, let me respectfully remind Prof. Bonney that it is not everything. It so happens that I too have a stake in the “banded gneisses” of ‘the Lizard district, and my field-work there showed me that the whole of his “granulitic” group of schists were rocks of true igneous origin, a fact forced upon me without the aid of the microscope; and further, that the other schists in which the Professor describes current-bedding and ripple-drift, etc., etc., I strongly suspected to have had also an igneous origin, and these appearances due to very different causes, facts which have since been corroborated by a high authority. So much for the use and non-use of the microscope, an instrument in research which I do not undervalue, and which I mean to become better acquainted with. Tt is, however, against the tone of the Professor’s letter that I complain, and I would invite him (and the rest of your interested readers) to compare the portion of it relating to myself with the last paragraph of his own article in “ Nature” for November 10th. 59, Furer Srreet, Torquay, Dec. 15, 1887. ALEX. SOMERVAIL. Correspondence—Dr. H, H icks. | 47 THE MAMMOTH AND THE FLOOD. We have received a somewhat lengthy communication from Mr. H. H. Howorth, M.P., in which he reminds us that so recently as 1880 Sir Andrew Ramsay expressed the opinion that “from the Laurentian epoch down to the present day, all the physical events in the history of the earth have varied neither in kind nor in intensity from those of which we now have experience.” (Address to Geol. Section, Brit. Assoc., Swansea.) We are glad to be in sympathy with Mr. Howorth in his opposition to this doctrine, but we do not believe it is upheld by many geologists at the present day, nor is it taught in modern text-books. (See Geology, by A. H. Green, Ed. 3, 1882, pp. 694—696; Text-Book of Geology, by A. Geikie, Hd. 2, 1885, pp. 8, 178; Outlines of Geology, by James Geikie, 1886, p. 3.) Mr. Howorth contends that over the greater portion of the Harth’s surface there is no such denudation going on (or even possible) as that which has taken place in past times. We have not disputed the notion that excessive denudation may have taken place in former times, for instance, during the Glacial period. Mr. Howorth, how- ever, objects to the employment of the term Denudation to include the action of springs and rivers in carrying away the soluble constituents of rocks! We are aware that literally the term is inapplicable, but in nearly every geological work it is used to signify the removal of material from any portion of the land. Mr. Jukes-Browne has indeed suggested that the word Detrition be used in this sense in place of Denudation, but we are averse to the introduction of new names, when the old ones are sufficiently intelligible. In reference to this subject we may refer Mr. Howorth to a work by Mr. Mellard Reade on “Chemical Denudation in relation to Geological Time.” Epir. Grou. Mae. THE DIMETIAN OF ST DAVIDS. Sir,—Mr. Mellard Reade’s paper in the GroLoctcaL Magazine for December on the Dimetian of St. Davids contains such striking evidence of a want of acquaintance with the subject, and such hasty conclusions founded on erroneous observations, that I should not consider it necessary to reply to it, were it not that a definite piece of so-called evidence is given which may lead to some misapprehen- sion if not corrected. The piece of evidence which he gives to prove “that the rock is not in any sense Archean, but is post-Cambrian, and intrusive,” occurs in the following passage relating to the sections at Porthclais : ‘‘ At a distance of about 50 feet north of this contact and embedded in the granite is a vein of green shale about 18 inches across and another about 10 feet nearer to the contact about six inches across. 1 As Mr. Howorth reminds us in his letter that the more important issues raised by his Reviewer (see Grot. Mac. October 1887, p. 473) can only be properly discussed when his second volume appears, we are content to await the issue of that work— the limited space at our disposal not admitting of the publication of lengthy letters in reply to Reviews.—Epir. Gru. Maa. 48 Correspondence—Dr. H. Woodward. Both these veins of shale, but especially the thinner one, have a rudely columnar structure at right angles to their direction. Excepting that this shale is a little more indurated and more like - slate in its constitution, it is similar to the Cambrian green shales that overlie the basal conglomerate. These veins are in my view undoubtedly part of the Cambrian shale entangled in the granite, so that the granite must be post-Cambrian.” Now, Sir, these veins are perfectly well known to all who have examined the sections at Porthclais, but it has been reserved for Mr. Reade to venture to call them Green Cambrian Shales. Those who have examined these veins with any care have had no difficulty in recognizing in them the ordinary behaviour of igneous rocks, and in proving after a microscopical examination that they are diabase dykes! Such dykes, as is well known, are common in the Dimetian, and they have been frequently referred to in my papers. Mr. Reade would therefore have acted more wisely, if, before publishing his views, he had taken the trouble to read more of what had been written on the subject, and also had consulted a petrologist as to the nature of the rocks he was dealing with. Henpon, Dec. 3, 1887. Henry Hicks. ON ETOBLATTINA, A LARVAL COCKROACH FROM THE COAL- MEASURES OF KILMAURS, AYRSHIRE; DISCOVERED BY MR. LINTON, OF KILMARNOCK. My attention has been called by Mr. Robert Kidston, F.G.S., to a serious omission made by me in my notice of Htoblattina Peachit in the GronocicaL Macazrne for October, 1887, p. 432. It is true that the specimen was forwarded to me by my friend, Mr. B. N. Peach, of the Geological Survey of Scotland, but I am now informed that it was found by a private geologist, Mr. Linton, of Kilmarnock,’ and he it was (and not the friend who sent it to me) whom I should have specially mentioned as being the discoverer. I regret exceedingly my carelessness in not making further inquiries of Mr. Peach as to its ownership before setting out to describe this interesting Carboniferous treasure, and I take this opportunity to thank Mr. Linton most cordially for placing it so generously at Mr. Kidston’s disposal for examination. We are all so deeply indebted to the persevering labours of such private geologists, as Mr. Linton, that I, for one, would be the last to omit to award them their full meed of honour. 129, Beaurorr Street, S.W. Henry Woopwarp. 1 This gentleman entrusted it to Mr. Kidston to be described. Mr. Kidston transferred it to Mr. Peach, who subsequently transmitted it to the writer—H.W. Western AvsTRALIAAWA—Mr. Harry Pace Woopwarp, F.G.S., F.R.G.S. (eldest son of Dr. Woodward, F.R.S., V.P.G.S.), who served for more than three years under Mr. H. Y. L. Brown, F.G.S., as Assistant Government Geologist in South Australia, has been appointed by Her Majesty’s Secretary of State for the Colonies to the post of Govern- ment Geologist for Western Australia. Only a very small portion of this, the largest of the Australian Colonies, has at present been examined by a geologist. Mr. Woodward left for Perth on the 2nd of December last.—Z7he Trmes, Dec. 8, 1887. GEoL. Mac. 1888. DECADE III. Vou. V.. Pu. IV. Specimens or Eozoén CanapEnse (Dawson), To 1LLusTRaTE Sir J. W. Dawson’s PAPER (p. 49). GEOLOGICAL MAGAZINE. NEW SERIES: “DECADE liz" VOEWeV. No. II—FEBRUARY, 1888. @l EG sEIN PASE Ake aCe se Se BOs J.—Note on New Facts rexatine To Eozoon CanapeEnse.! By Sir J. Witt1am Dawson, LL.D., F.R.S., etc., ete. (PLATE IY.) YHE late Dr. Carpenter had undertaken an elaborate series of investigations of Hozoon, based on all the material collected by myself and others in Canada, with the view of preparing a complete and exhaustive memoir on the subject. In consequence of this arrangement the new facts obtained for several years have remained unpublished. Unhappily the work was left at his lamented decease in a very incomplete state. The present note is intended, without entering into any contro- verted points, to notice some new facts respecting the fossil and its state of preservation, which have been disclosed within the few past years. 1. Form of Hozoon Canadense. Hitherto this has been regarded as altogether indefinite, and it is true that the specimens are often in great confluent masses or sheets, the latter often distorted by the lateral pressure which the limestone has experienced. The specimen from Tudor, however, figured by Sir W. H. Logan in the ‘Quarterly Journal of the Geological | Society,’ 1867, p. 253, and that described by me in the ~ Proceedings of the American Association’ in 1876, and figured in my work “ Life’s Dawn on Earth,” gave the idea of a turbinate form more or less broad. More recently additional specimens weathered out of the limestone of Cote St. Pierre have been obtained by Mr. E. H. Hamilton, who collected for me at that place ; and these, on com- parison with several less perfect specimens in our collections, have established the fact that the normal shape of young and isolated specimens of Hozoon Canadense is a broadly-turbinate, funnel-shaped, or top-shaped form, sometimes with a depression on the upper surface giving it the appearance of the ordinary cup-shaped Mediterranean sponges. (See Pl. 1V. Fig. 1.) The photographs exhibited show this appearance in two specimens. ‘These specimens also show that there is no theca or outer coat either above or below, and that the laminee pass outwards without change to the margin of the form, where, however, they tend to coalesce by subdividing and bending together. The laminz are thickest at the base of the inverted cone, and become thinner and closer on ascending, and at the top they 1 Read at the Meeting of the British Association, Sept. 5, 1887. DECADE III.—VOL. V.—NO. II, 4 090 «Sir Wm. Dawson—New Facts as to Eozobn Canadense. become confounded in a general vesicular or acervuline layer. I feel now convinced that broken fragments of this upper surface scattered over the sea-bottom formed those layers of Archeospherine which at one time I regarded as distinct organisms. It is to be observed, however, that other forms of Eozoon occur. More especially there are rounded or dome-shaped masses, that seem to have grown on ridges or protuberances, now usually represented by nuclei of pyroxene. 2. Pores or Oscula. In the large number of specimens of Eozoon which have been cut or sliced in various directions, and are now in our Museum at Montreal, it has become apparent that there are more or less cylindrical depressions or tubes, sometimes filled with serpentine and some- times with inorganic calcite, crossing the lamine at right angles. These seem to occur chiefly in the large and confluent masses, and are without any regular or definite arrangement. In some of the narrower openings of this kind the lamine can be observed to sub- divide and become confluent on the sides of these tubes, in the same manner as at the external surface. This circumstance induces me to believe that these are not accidental, but original parts of the structure, and intended to admit water into the lower parts of the masses. A characteristic example of a fortunately weathered specimen is seen in the photograph accompanying this paper. (See Pl. IV. Fig. 2.) A central canal of a similar kind is well shown in the accompanying illustration. Section of the base of a turbinate or top-shaped Hozoom. This specimen shows an osculiform, cylindrical perforation, cut in such a manner as to show its reticulated wall and the descent of the lamine toward it. Two-thirds of natural size. Coll. Carpenter. [This illustration (from Prof. Prestwich’s ‘‘Geology,’’ vol. ii. p. 21) has been courteously lent by the Clarendon Press, Oxford. ] Sir Wm. Dawson—New Facts as to Eozobn Canadense. 51 3. Beds of Fragmental Eozoon. If Eozoon was an organism growing on the sea-bottom, it would be inevitable that it would be liable to be broken up, and in this condition to constitute a calcareous sand or gravel. I have already in previous papers described Laurentian limestones containing such fragments from the Grenville band at Cote St. Pierre, from the Adirondack Mountains in New York State, from Chelmsford, Massachusetts, and from St. John, New Brunswick, as well as from Brazil, and the Swiss Alps. Indeed, the Laurentian limestones of most parts of the world hold fragmental Hozoon. In the Peter- Redpath Museum are some large slabs of Laurentian limestone sawn under the direction of Sir W. E. Logan, and showing irregular layers and detached masses of Eozoon with layers or bands of lime- stone and of ophiolite. These are evidently layers successively deposited, though somewhat disturbed by subsequent movements. On selecting specimens from the white and more purely calcareous layers, I was pleased to find that they abound in fragments of lamine of Hozoon, having the canals filled either with dolomite or with colourless serpentine. Other portions of the limestone show the peculiar granulated structure characteristic of the calcareous laminze of Eozoon, but without any appearance of canals, which may in this case be occupied with calcite, not distinguishable from the substance of the laminew. There are also indications in these beds of limestone of the presence of Hozoon not infiltrated with serpentine, but having its lamine either compressed together, or with the spaces between them filled with calcite. There are other fragments which, from their minute structure, I believe to be organic, but which are apparently different from Hozoon. 4. Veins of Chrysotile. I have in previous papers abundantly shown that the veins of fibrous chrysotile which abound in serpentinous limestones of the Laurentian are of secondary aqueous origin, as they fill cracks or fissures not merely crossing the beds of the limestone, but passing through the masses of Hozoon and the serpentinous concretions which occur in the beds. ‘They must, therefore, have been formed by aqueous action long after the deposition, and in some cases after the folding and crumpling of the beds. In this respect they differ entirely from the laminz of Hozoon, which have been subject to the same compression and folding with the beds themselves. The chrysotile veins have, of course, no connection with the structures of Hozoon, though they have often been mistaken for its more finely tubulated portion. With respect to this latter, I believe that some wrong impressions have been created by defining it too rigorously as a “proper wall.” In so far as I can ascertain, it consisted of finely divided tubes similar to those of the canal- system, and composed of its finer subdivisions placed close together, so as to become approximately parallel, as in the photograph No. 4, sent herewith. 52 = Sir Wm. Dawson—New Facts as to Foz06n Canadense. 5. Nodules of Serpentine. Reference has been made in previous papers to the nodules and grains of serpentine found in the Eozoon-limestone, but destitute of any structure. These nodules, as exhibited in the large slabs already referred to, have however often patches of Eozoon attached to, or imbedded in them, and they appear to indicate a super- abundance of this siliceous material accumulating by concretionary action around or attached to any foreign body, just as occurs with the flints in chalk. The layers of grains and serpentine parallel to the bedding appear to be of similar origin. 6. State of Preservation. Recent observations more and more indicate the importance and frequency of dolomite as a filling of the canals, and also the fact that the serpentine deposited in and around the specimens of Eozoon is of various qualities. Dr. Sterry Hunt has shown that the purely aqueous serpentine found in the Laurentian limestones is of different composition from that occurring with igneous rocks, or as a product of the hydration of olivine. There are, however, different varieties even of this aqueous serpentine, ranging in colour from deep green to white; and one of the lighter varieties has the property of weathering to a rusty colour, owing to the oxidation of its iron. These different varieties of serpentine will, it is hoped, soon be analysed, so as to ascertain their precise composition. ‘The mineral ' pyroxene, of the white or colourless variety, is a frequent associate of Hozoon, occurring often in the lower layers and filling some of the canals. Sometimes also the calcareous laminz themselves are partially replaced by a flocculent serpentine, or by pyroxenic grains imbedded in calcite. 7. Other Laurentian Organisms. In a collection recently acquired by the Peter-Redpath Museum, from the Laurentian of the Ottawa district, are some remarkable cylindrical or elongated conical bodies, from one to two inches in diameter, which seem to have occurred in connection with beds or nodules of apatite. They are composed of an outer thick cylinder of granular dark-coloured pyroxene, with a core or nucleus of white felspar ; and they show no structure, except that the outer cylinder is sometimes marked with radiating rusty bands, indicating the decay of radiating plates of pyrite. They may possibly have been organisms of the nature of Archeocyathus; but such reference must be merely conjectural. 8. Cryptozoum. The discovery by Prof. Hall, in the Potsdam formation of New York, and by Prof. Winchell in that of Minnesota, of the large laminated forms which have been described under the above name, has some interest in connection with Eozoon. I have found frag- ments of these bodies in conglomerates of the Quebec group, associated with Middle Cambrian fossils; and, whatever their Sir Wm. Dawson—New Facts as to Eozo6n Canadense. 53 zoological relations, it is evident that they occur in the Cambrian rocks under the same conditions as Eozoon in the Laurentian. I find also in the Laurentian limestones certain laminated forms usually referred to Eozoon, but which have thin continuous lamine, with spongy porous matter intervening, in the manner of Cryptozoum or of Loftusia. Whether these are merely Eozoon in a peculiar state of preservation or a distinct structure I cannot at present determine. 9. Continuity and Character of containing Deposits. At a time when so many extravagant statements are made respect- ing the older crystalline rocks, it may be proper to state that all my recent investigations of the Middle Laurentian vindicate the results of the late Sir William Logan as to the continuity of the great lime- stones, their regular interstratification with the gneisses, quartzose gneisses, quartzites, and micaceous schists, and their association with bedded deposits of magnetite and graphite, and also the regularity and distinctly stratified character of all these rocks. Farther, I regard the Upper Laurentian, independently of the great masses of Labradorite rocks, which may be intrusive, as an important aqueous formation, characterised by peculiar rocks, more especially the anorthite gneisses. I am also of opinion that the so-called crystalline Huronian rocks of the country west of Lake Superior are stratigraphically, and to a great extent lithologically, equivalent to the Upper Laurentian of St. Jerome and other places in the Province of Quebec, differing chiefly in the greater or less abundance of intrusive igneous rocks. 10. Imitative Forms. The extraordinary mistakes made by some lithologists in studying imperfect examples of Eozoon and rocks supposed to resemble it, and which have gained a large amount of currency, have rendered necessary the collection and study of a variety of laminated rocks, and considerable collections of these have been made for the Peter- Redpath Museum. They include banded varieties of dolerite and diorite, of gneiss, of apatite and of tourmaline with quartz, laminated limestone with serpentine, graphic granites, and a variety of other laminated and banded materials, which only require comparison with the genuine specimens to show their distinctness, but many of which have nevertheless been collected as specimens of Hozoon. I do not propose to enter into any detailed description of these here, but hope, with the aid of Dr. Harrington, to notice them in forth- coming Memoirs of the Peter-Redpath Museum. Postscriet.—It has been suggested by Mr. Julien’ and others that Hozoénal structure may be due to the alternation of mineral layers formed in the passage-beds between concretions and their enclosing mass. ‘The objections to this view are : 1. Laminated passage-rocks and laminated concretionary forms 1 Proceed. Amer. Assoc. vol, xxxiil. 1884, pp. 415, 416. 54 Prof. T. G. Bonney—Rounding of Alpine Pebbles. have only simple laminz, whereas Hozoon has connected or reticu- latory lamine. : 2. Laminated passage-rocks have no structure other than crystalline. Eozoon has beautiful tubulation in its calcareous walls, besides large tubes or oscula. 3. Sometimes (not usually) pyroxene is the siliceous part of Eozoon; or, as we hold, the mineralizing agent. More usually it is serpentine, sometimes loganite, or dolomite, or mere earthy lime- stone. It is not possible that all these minerals should assume the same forms. 4, Pyroxene and serpentine both occur in nodules and bands in the Laurentian limestones, and in most cases without any traces of Eozoon, while Eozoon occurs in the limestone remote from such nodules and bands, where no passage of any kind can occur, and presents distinct forms. d. There are only two localities known to me, one in a quarry near Cote St. Pierre, and one at Burgess, where a bed with badly- preserved Hozoon occurs in a manner which would not even suggest an idea. Pyroxene is present in the one case, and loganite in the other. 6. I have often thought of this suggested explanation, and have compared Hozoon with all sorts of banded and passage-rocks taken from the Laurentian and other formations, but have seen no reason to adopt such a view for Eozoon. I may add that in the Peter- Redpath Museum at Montreal I have accumulated a very large number of laminated and passage-rocks and concretions for purposes of comparison. 7. How on such an hypothesis can we explain the beds of lime- stone composed of or filled with fragments of Hozoon ? EXPLANATION OF PLATE IV. Fig. 1.—Small specimen of ZHozoén, separated from the matrix, and showing a turbinate form. Nat. size. Coll. Dawson. : Fie. 2.—Weathered specimen of Hozodn, showing a section through the middle, with two cylindrical, osculiform, vertical tubes. The modification of the lamine at the sides of the tubes is similar to that at the exterior. Nat. size. Coll. Dawson. IJ.—Opsrrvations on THE RounpING or PEBBLES BY ALPINE Rivers, with a Nore oN THEIR BEARING UPON THE ORIGIN OF THE Bunter ConGLOMERATE.! By Pror. T. G. Bonnzy, D.Se., LL.D., F.R.S., F.G.S. HEN preparing my address to Section C in 1886, I had much need of information as to the amount of rounding which takes place in rock fragments when transported by rapid streams. Useful information and references are given in Dr. A. Geikie’s Text Book? and in De Lapparent’s “ Traité de Géologie,” * and there are the ex- 1 A Paper read at the Meeting of the Brit. Assoc. (Section C) in Manchester, 1887. 2 Book iii. pt. ii. sec, ii. 3 Book ii. sec. i. ch, ii. Prof. T. G. Bonney—Rounding of Alpine Pebbles. 55 perimental researches of Daubrée in his “ Géologie Experimentale ” ;* but from neither these nor other sources (so far as known to me) could I obtain what I wanted. I must, however, admit that I am less familiar with the talus heap of geological literature than I should be, and prefer making observations in the open air, to hunting for records of them in a library. So, as I had some opportunities of doing the former during my journey last summer, I record the results in the hope that they may be useful to others; first heartily thanking my companion, the Rev. EH. Hill, for constant co-operation and as- sistance. These observations may be arranged roughly in three groups, which correspond with the three stages in the physical history of an Alpine river. It begins as a series of torrents, born for the most part high up on the mountain side from snow-bed and glacier. Its next stage is that of a single torrent rushing over the bed of an Alpine valley, still bounded on either hand by mountain ranges ; the third, and last for our present purpose, begins as it issues from the ‘gates of the hills’ and commences its journey through the lowland plains. In the first of these stages its fall is always rapid, as it leaps from ledge to ledge, or even from crag to crag, descending not unfrequently at average rates of 250 feet to 500 feet in a mile, or along slopes averaging from 3 to 6 degrees. Thus it is a rushing roaring cataract, able always to sweep along boulders full a couple of feet in diameter, and often much larger blocks. In the second stage the fall becomes more gentle, though occasionally, es- pecially at the commencement, there may be a partial return to the former conditions; tributary streams also are being constantly re- ceived, which have only passed through that stage; but gradually as the valley widens the torrential character is lost, and the river flows as a strong swirling stream, in which intervals of actually broken water are rare. Lastly, after emerging from the mountains, and thus being cut off from all further contributions from torrents, it sweeps along with a strong steady flow, “hasteless but restless,”’ perhaps one of the grandest representations of unobtrusive power that can be seen in Nature. Obviously in observations of the present kind, little more than general results can be given. A river is constantly receiving tributaries, which discharge into it materials, not only differing in hardness or tenacity, but also in the amount of detrition which they have undergone. The strength also of its current varies from time to time. In some districts, or at certain seasons, what in the morning was a dry stream-bed, in the afternoon may be a roaring torrent. Further it is extremely difficult to determine the velocity with which a mountain torrent flows. In the case of some of the larger and less rapid rivers we made rough estimates by watching floating bits of wood and the like; they varied from about 21 to 4} miles an hour. An approximation also may be made from observing the size of the pebbles in the bed. A table is quoted in most text 1 Vol. i. sec. ii. ch. i. 56 Prof. T. G. Bonney—Rounding of Alpine Pebbles. books which may be thus extended theoretically for pebbles formed of an average rock. Diameter of pebbles Miclocitrotistream just moved. meh yess ce eeraae 2 feet per second, 1°3638 miles an hour. 2oinches seer 2-82 feet ,, 3}, hp Gouapadaod0ced BPG oe lil Ay i lionaaseaaaeiee 4:00 ,, 45 2°7276 4, 7% B) 59) Goasaobon00006 AAAS leas G. pisr hve sildeiaeiseetetstes BOO 5 op gg ofostes seeoeeeeee CODD) oo higg Je Ein qoneadastoccdee ORGON stan ys Ei any andtiodssdacasat COONS ees 4:0914 ,, 30 Hence we may infer that a deposit in which fairly well-rounded pebbles of about 4 inches diameter are so common as to be characteristic, is the result of a stream which flowed pretty steadily at a rate of about 2% miles an hour, and one in which they are about 8 inches or 9 inches diameter, is the result of a stream flowing about 4 miles an hour. It must, however, be remembered that this would be the velocity at the bottom of the stream, which is estimated at about half that of the surface in the middle. Great variability in the size of the pebbles, and especially the presence of frequent boulders or subangular blocks much exceeding the average size,—as, for example, a mixture of blocks something like two feet in diameter, with pebbles generally not more than one foot in diameter, and commonly less,—is indicative of torrential discharge. For brevity I use the term ‘ Alpine rock’ to mean gneisses, more or less granitoid, and mica-schists of various kinds, together with hornblendie or chloritic schists, and possibly serpentines—that is to say rocks, which are in all cases crystalline, and in some at least of lgneous origin. Grovp I. Bed of Romanche above Villard d’ Aréne (Dauphiné).—This stony plain lies at a height of about 5000 feet above the sea—at the foot of a steep descent of 1500 feet. The river is fed by streams from snow-beds and glaciers, and its sources may be roughly estimated as from 7000 to 8000 feet above the sea, and at distances of three to five miles’ from the place of observation. The stones are chiefly granitoid rocks, but some are Jurassic mudstones (these are from near at hand). Leaving the. latter out of consideration, the stones, which vary from boulders downwards, are generally subangular, even the smaller pebbles not being well rounded. Bed of torrent through village at Windisch Matrei (Tyrol).—This comes down from the valley running up to the Kalser Thorl, and probably has descended some 2000 feet. The ‘torrential’ character is indicated not only by the variability in the size of the stones and boulders, but also by the high walls which protect the village from its ravages. Stones from Sins. to 6ins. diameter were common; others up to about a foot diameter were fairly common, and larger occurred. 1 Distances in this paper, unless otherwise stated, are measured on a map, and so are obviously less than the actual course of the stream, Prof. T. G. Bonney—Rounding of Alpine Pebbles. 57 Well-rounded pebbles rare, and never large. Alpine rock, including some serpentine. Little plain at foot of Gross Venediger.—Enclosed by cragg mountains ; stones brought down by various torrents, chiefly from snow-beds and glaciers, descending precipitously from 1000 to 2000 feet. Boulders and pebbles of Alpine rock, the latter not much rounded, having generally little more than the corners worn away ; only some of the smaller and softer are moderately rounded. Bed of Stillupthal (Zillerthal).—Glaciers and snow-beds surround the head of the valley, the floor of which rises rather gradually. Deposits torrential in character. Alpine rock. Observation at 3500 feet, where the stream flowed with only a slightly broken surface. Stones subangular to imperfectly rounded, mostly 3ins. to 4 ins. in diameter, a few nearly afoot. A couple of miles or so lower down, at a height of 2950 feet, the flow is more rapid: many pebbles 3 ins. to 4ins. in diameter, varying from rounded subangular to subangular rounded, together with larger boulders of all sizes up to at least a yard diameter, some of which were moderately rounded ; chiefly gneiss and granitoid rock. Below Ginziing, Zillerthal.—Place of observation about 8230 feet: the river being formed by confluence of a torrent from the Floiten- thal (a glen about nine miles long, enclosed by steep mountain walls, seamed by cascades and rising at the upper end from 9000 feet to 11,000 feet, and terminated by a rapid descent through a rocky gorge) and that from the Zemmthal (a valley perhaps three miles longer, which rises on the whole more gradually, and is enclosed by mountains somewhat lower). Materials, various Alpine rocks. All sizes up to about a foot in diameter common, but many exceed this ; blocks up to two or three feet diameter not being rare: much variability in the amount of rounding, many being quite subangular, but some fairly well rounded,! these chiefly a rock resembling a tonalite not rich in quartz and a felspar-actinolite rock (rather rare). The former I believe occurs in situ far back in both these glens. Group II. We may commence by following the course of the river last described. At Mairhofen (2096 feet) by the Calvarienberg, stones commonly 4 ins. to 6ins. diam., but both smaller and larger, are present; some blocks are quite a yard in diameter. Amount of wearing very variable ; almost the only well-rounded pebbles are the above- named ‘tonalite’; next to that is a porphyritic gneissoid rock, common in the Stillupthal. Alpine rocks, with some subcrystalline limestone. At Zell (four miles and a half and more than 200 feet lower down). Stream strong, surface rather broken in the swifter parts. Stones mostly from rounded subangular to fairly rounded, commonly from about 4ins. to 6 ins. smaller of course occur, but rarely one over 1 It must be remembered that when a torrent descends precipitously over a bed of rock, not a few stones may receive an exceptional amount of rounding by being whirled about in ‘ potholes.’ 58 Prof. T. G. Bonney—Rounding of Alpine Pebbles. 1 foot diameter. Mostly granitoid gneisses of a somewhat friable character. I have in my note book observations of the Inn at Jenbach, Inns- bruck, and near to Landeck, of the Isel between Windisch Matrei and Lienz, of the Drave at the latter place, of the Hisack near Brunecken, and at Bozen, of the Romanche at Vizille, and the Isére at Grenoble; but it is perhaps needless to quote them in detail, as to a great extent they would be repetitions of the above statements. Suffice it to say the stones commonly range from about 8 ins. to 6 ins., smaller and larger occurring, in the latter case not seldom up to nearly 1 foot, with occasional large boulders; that the amount of round- ing is variable, but the majority of the first named may be described as from subangular to moderately rounded —well-rounded pebbles being generally not common.' Materials, Alpine rocks with variable amounts of limestones and grits. At Bozen also the igneous rocks of the district were well represented. Group III. The first case examined was the Po at Turin. The river and its tributaries have now flowed over about 85 to full 50 miles of plain. The principal streams which feed it descend valleys from about 15 to over 30 miles long, and may be reckoned as having their sources at from 5000 to 6000 feet above the sea.” The stones exposed near the banks consist chiefly of Alpine rocks, are commonly 3 ins. to 4 ins. diameter, occasionally running up to about 8 ins. together of course with smaller. As a rule they are not well rounded, retaining more or less a subangular outline, though the corners and edges are worn off. In travelling from Turin to Milan, and thence to the Lago di Garda, several rivers are crossed, and sections obtained of the sub- stratum of the great alluvial plain of Piedmont and Lombardy. The results in regard to the former may be summarized in a tabular form. Approximate length of river. Diameter of Pebbles. Name. Condition. Among the Mts.| Over the plain.| Average. | Maximum. Stura ...| 18 miles. 20 miles. Sito) 4a p6"| rhay GC Bee Orco...... 2201, 1 Site abt. 4” 6” | Fairly well rounded. Sesion i265 Be. abt. 2” |rarely>4” | Moderately __,, Ticino ... aN 202 3” to 4” p » ” Adda’ °.. te PAD 3” to 4” 26’ | Fairly well a5 The main streams of the Ticino and Adda have most of their Alpine pebbles stopped by the Lakes of Maggiore and Como, but * Our estimates of the rates of flow varied from about three to four and three- quarter miles an hour. I expect these great mountain rivers run at an average pace of nearly four miles an hour, and at certain seasons considerably exceed this. * I mean as fairly strong streams; in some cases brooklets would be higher, and _ of course the snow-beds about the sources of the Po rise up in places to quite 9000 feet. Prof. T. G. Bonney—Rounding of Alpine Pebbles. 59 they receive some sub-Alpine tributaries. Consequently, limestone pebbles characterize their gravels. Besides these observations we repeatedly had indications of the gravel of the great plain, either from the stones scattered over the fields, from ballast pits, or from railway cuttings. Here also pebbles often about 3 ins. or 4 ins. are common, with occasional larger ones. In fact, they frequently are very similar in size to those of the Bunter Conglomerate in Staffordshire, but generally not quite so well rounded. Limestone becomes more common, as might be expected, as we proceed eastwards. This remark holds, I believe, of the great plain of Lombardy as far as the south end of the Lake of Garda. Old drifts, repeatedly seen between Lyons and Grenoble, in size, amount of rolling and arrangement, bore a remarkable resemblance to the Bunter pebble-beds of Staffordshire (except that the materials were mainly limestone). This was particularly the case near Virencal, where the section was some 40 feet high, and the pebbles were parted by streaks or bands of sand. The old drifts of the Rhine at Stein and near Bale are very similar. In regard to the Lake of Garda, I endeavoured to ascertain the action of its waves on the beach pebbles. These are abundant to the east of Desenzano, and they have evidently been derived from the north. They are fairly well rounded, but seeing that similar pebbles, about as well rounded, occur in the drifts of which its banks consist, no inference can be drawn from them. But I observed that well-rounded pebbles had been formed on the shore from fragments of a soft red brick; also that shards of ordinary red earthenware had been sometimes fairly well rounded. It must be remembered ‘that the Lago di Garda is noted of old for its waves, ‘“fluctibus et fremitu assurgens, Benace, marino;” but, as a rule, the great sub- Alpine lakes have not, so far as I have noticed, much effect on rock fragments. It is difficult to give precise statements of the amount of fall in the Alpine rivers; but the following are rough approximations, calculated from the heights quoted in guide-books, which of course do not give the exact level of the river at the place, and from the distances by road, which, at any rate when the valley is tolerably level, are generally rather sometimes considerably shorter than the river course. : The Inn, from St. Moritz to Samaden (three miles) falls about 65°3 feet per mile; from Samaden to Landeck (794 miles) about 37°3 feet per mile; from Landeck to Innsbruck (52% miles) about 13-8 feet per mile; from Innsbruck to Jenbach (23 miles) 3°83 feet per mile (I believe rather more, for I think the height given for Jenbach is above the Inn—possibly 80 or 100 feet too great). The Ziller from Ginzling to Mairhofen (about 73 miles) falls 155-5 feet per mile; from Mairhofen to Zell (44 miles) 17-8 feet per mile; from Zell to Jenbach about 4:6 feet ora little more (this, for the above reason, and as the embouchure of the Ziller is not at Jenbach itself, is a very rough estimate). 60 Prof. T. G. Bonney—Rounding of Alpine Pebbles. The Isel (including a tributary) : Tauern Haus to Windisch Matrei (about 10} miles) about 164 feet per mile; Windisch Matrei to Lienz (18 miles) 58 feet per mile. It is very difficult to estimate the fall in the Po and its tributaries. Turin is 602 feet above the sea, probably the edge of the plain is about 800 feet. That would give a fall of about 4 feet per mile. In the tributary valleys I should think that the fall would be not less than 100 feet per mile. As an example of a true torrent, the Reuss between Andermatt and Amsteg falls about 212 feet per mile; from the latter place to the Lake of Lucerne only 26°38 feet per mile. The facts thus collected appear to me to warrant the following conclusions :— 1. The rapidity with which a pebble is formed depends ceteris paribus on the nature of the rock. 2. Pebbles are rounded with comparative rapidity when the descent is rapid; that is, when they are dashed down rock slopes by a roaring torrent, capable of sweeping along blocks of far greater size. 3. Pebbles are rounded with comparative slowness when the descent is gentle, and the average pace of the river is just about able to push them along its bed. 4, As indicated by Daubrée’s interesting experiments, the process of rounding ceteris paribus always goes on more rapidly at first. In the above observations the rocks (with the exception of some vein-quartz which generally proved a rather intractable material) may be taken as ranging in hardness from rather above 8 to about 6. The limestone pebbles would probably range from 8 to 4, and there would be chemical action in addition. The Alpine rocks, as a rule, would probably range from 5 to 6, for though quartz is present, there is always a good amount of felspar or mica. The easy rounding of the more micaceous schists, due to their softness, is to some extent counteracted by their fissility. If, then, we find in any conglomerate, a large number of well- rounded pebbles of a rock not less hard than felspar, we are justified in concluding that they are the deposit of a river which, in any case, has had a course of several miles, and has either descended as a very rapid stream from snow-capped mountains of considerable elevation, the detritus, in short, of a strong, full, torrent in a valley running down from a great mountain-chain, or of a river which, rising at a more moderate elevation and swollen by many tributaries, has flowed for a very much longer distance. Perhaps we might venture to say, as a rough standard of comparison, that the effect of a thousand feet of rapid descent is equivalent to that of the more leisurely traverse of at least twenty miles, so that fairly well rounded pebbles of a rock with hardness not exceeding 6 signify at least either a rapid descent of three thousand feet or a journey at a less speed of sixty miles.! ' Prof. Daubrée (Géol. Experim. vol. i. sec. ii. ch. v.) obtained experimentally a distance of a little less than 16 miles for the manufacture of a rounded pebble of granite, but this must be regarded as the least possible distance, for in his experiments the fragments would be knocked one against another much more than in transport by a stream, except perhaps in a ‘‘ pothole.”’ Col. McMahon—Granite of the Himalayas. 61 If then we consider the question of the origin of the Bunter pebbles in the light of these facts, two suggestions as to their origin are at once shown to be impossible. The majority of the pebbles are a very hard quartzite, are from 2 ins. to 4 ins. diameter, and are well rounded. Hence they must have had a much longer descent or a much longer journey than that above named. By one author they have been referred to a concealed ridge of Palzozoic rock in Hastern England,! by another to a similar ridge in Central England, of which the Malvern and Lickey Hills, etc., are the monumental outcrops.’ I have already pointed out the difficulties attending both these views, so far as regards the nature of the materials, their enormous volume and their disposition. I have commented on the confused views of the latter author, both as to lithology and physical geology; but the observations above made effectually dispose of one of his criticisms, that pebbles coming from Scotland would have been “reduced to sand” before reaching Staffordshire,—a criticism indeed which even the knowledge in our possession at that time did not justify. They also indicate that unless we maintain the Bunter Beds to be a marine deposit (which I do not suppose will find any support with modern geologists), its pebbles can only have been formed by strong and full rivers. These, if from insular lands, must have issued from lofty mountains ; if from continental, must have flowed with strong stream for long distances. Considering the hardness of the materials, we may demand insular mountains even higher than the Alps, or rivers with courses exceeding a couple of hundred miles in length, of fuller volume and stronger stream than now exist in Britain. The sources for the Bunter pebbles then, proposed by either of these authors, Utopian at best, cannot be made to accord with the facts which I have recounted, while the general resemblance of the Bunter Beds to the conglomerate of the Nagelflue, and to the gravel of the plains which stretch away from the feet of the Alps, renders the northern origin of these pebbles,—where continental conditions did prevail and identical pebbles still exist in older conglomerates—a far more probable theory. Il].—Tue Gyetssose GRANITE OF THE HIMALAYAS. By Colonel C. A. McManon, F.G.S. HAVE read with great pleasure Mr. R. D. Oldham’s interesting article in this Magazine, for October, 1887, on the gneissose rocks of the Himalayas. Mr. Oldham concurs with me in assigning an eruptive origin for the more or less gneissose rocks at Dalhousie, the Chor, and for almost all those in the Satlej Valley; and as I have in my published papers expressly intimated ‘“ my belief that some of the crystalline rocks of the north-western Himalayas are metamorphic gneisses ” (Records Geol. Surv. India, vol. xviii. p. 110), I see no grounds for dissenting from his observations regarding the latter class of rocks. 1 Gzou. Maa. Dec. II. Vol. X. p. 285. ? Proc. Phil. Soc. Birmingham, vol. iii. p. 157; Gon, Mac. Dee, II, Vol. X. p- 199. This locality is practically included in the other. 62 Col. McMahon—Granite of the Himalayas. One remark, however, in Mr. Oldham’s article, tempts me to offer a few words of explanation in continuation of my last paper in the GxrotocicaL Macazine. Speaking of the gneissose-granite, Mr. Oldham expresses his belief “that the very slight foliation of the larger masses is principally a fluxion structure, while the more developed structure of the thinner bands, and near the margins of the larger masses, was produced in the solid but séill heated granite [the italics are mine] by the same causes—whatever they be—that led to the foliation of the adjacent sedimentary beds;” and in a footnote he remarks; “ In 1884 Colonel McMahon seems to have held an opinion somewhat similar to this (see Records Geol. Surv. India, vol. xvil. p. 72), but so far as I can understand his paper in the May Number of this MaGazinn, he has now abandoned it.” I hoped that I had made my meaning sufficiently clear; but as this does not appear to have been the case, a few explanatory remarks may not be out of place. The passage in my paper published in the Records Geol. Surv. India referred to runs as follows :—‘“‘ The conclusion at which I have arrived, on a consideration of all the facts of the case, is that the invasion of previously metamorphosed strata by gneissose granite, combined with the pseudo-foliation of the latter due to the pressure of hard strata on a partially cooled and imperfectly viscid rock, has imparted to the intruded rock the superficial appearance of being a member of the same metamorphic series as the schists and slates into which it has intruded. There is no inconsistency, I would point out in conclusion, in supposing that the rock which gives evidence of having passed through a stage of aqueo-igneous fusion was partially cooled and semi-viscid when’ actually intruded into the schists. Observation in our own time shows that there are pauses and long intervals in volcanic action; and doubtless similar pauses took place in plutonic action during which the cooling and partial consolidation of igneous masses went on and the larger por- phyritic crystals found in many of them were formed. The subse- quent motion of a partially consolidated viscid rock and its intrusion as a sheet between hard strata, or between the walls of a fault, would, it seems to me, naturally produce parallelism of structure, or pseudo-foliation, as long ago pointed out by Scrope and Naumann.” I have not gone back one iota from the view expressed in the above extract, and I am ata loss to understand why I should have been supposed to have done so. The observations given at pp. 219, 220, of the 1887 volume of this Macazing, seem to me to be merely a detailed explanation of the view more briefly expressed in the above extract. In the latter three conditions are noted; the partial consolidation of the granite before it was moved into place, traction action on the granite when it was squeezed into position ; and the ‘“‘ pressure of hard strata” upon the intruded mass. That partial consolidation had set in before the granite was moved into its present position seems implied by the pronounced porphyritic character of the rock. ‘All the facts connected with 1 Inthe Records the word is where—a senseless alteration of the text due to the Indian printer’s devil. Col. McMahon— Granite of the Himalayas. 63 these porphyritic lavas,” writes Professor Judd with reference to a somewhat different class of rock in his well-known work on Volcanoes, p. 256, “points to the conclusion that while the crystals in their ground-mass have separated from the liquefied materials near the surface, the large embedded crystals have floated up from ereat depths within the earth’s crust, where they had originally formed.” I do not mean to affirm that a similar inference would be safe in respect of all porphyritic rocks, plutonic as well as volcanic ; but I think we may safely draw that inference with regard to the porphyritic crystals in the Dalhousie rock, for in some places tongues, and veins, intruded into the adjacent schists are as distinctly por- phyritic as the main mass of the granite (Records Geol. Surv. India, vol. xv. p. 45), and I do not think any one would allege that the large porphyritic crystals in the small veins were formed i situ. The same conclusion must, I think, be arrived at when large porphyritic crystals are found (Records Geol. Surv. India, vol. xvi. p. 129) in a matrix so fine grained that the Dalhousie rock occasionally assumes the superficial appearance of a felspar porphyry. That the granite was, at the time of intrusion, partially cooled and imperfectly viscid, is almost conclusively proved by the con- dition of the foreign fragments included in it. At page 175 of the volume to which Mr. Oldham has referred (vol. xvii. of 1884) I wrote as follows:—‘In the case of the long splinter of schist, a fragment of which is depicted in the plate attached to this paper, it is clear that it must have been included in the granite when the latter was already partially consolidated, and had lost a considerable part of its heat. JI have found on other grounds, in my previous papers, that the gneissose-granite had partially con- solidated before it was intruded into the stratified rocks; and the evidence afforded by the fragment of schist under consideration con- firms this conclusion. The schist would not have retained its fine foliation had the granite been in a fluid state, and at the high heat indicated by that condition.” The reasons for coming to this con- clusion are given in detail in my paper. I may note in passing that the texture of the porphyritic granite immediately round the fragment of schist referred to is fairly granitic, and this fragment proves that the rock from which it was torn was in a foliated condition before the intrusion of the granite took place. The granitic structure of the granite compared with the fine foliation of the schist, a point that is well brought out by the heliogravure reproduction of a photograph given at p. 175, vol. xvii. Records Geol. Surv. India, appears to negative the assumption that the folia- tion of the Dalhousie granite and the foliation of the schists into, and through which, it was intruded, are both alike due to pressure- metamorphism operating after the intrusion of the granite. From the use of the words “still heated granite,” and from the context, ] am under the impression that Mr. Oldham is of opinion that the structural changes in the granite which resulted in folia- tion were produced before it had perfectly cooled down after its injection; if so, our views seem to be substantially identical. 64 Col. McMahon—Granite of the Himalayas. Whether he holds that the granite was injected in a fluid, or in a partially consolidated condition, is not so clear to me. Possibly if there is any apparent divergence in our views, it may be owing to my not having expressed mine in sufficient detail. Mr. Oldham, in the extract I have quoted, speaks of the condition of the granite when foliation was produced as “ solid but still heated.” (The italics are mine.) In my papers I have avoided the use of the word solid, and preferred to speak of the granite as being in “a partially cooled and imperfectly viscid’ condition, or as an “im- perfectly consolidated”? mass; but by the use of these expressions I contemplated a considerable advance towards solidity. In my article in the May, 1887, number of this Macaztnz, I stated that the ‘semi-plastic mass was subjected to enormous pressure; the mica was crumpled, and the crystals of felspar were cracked and ruptured.” These results, ] need hardly say, could not have been produced unless the solidification of those portions of the rock in which they are to be observed was in a somewhat advanced stage. But, on the other hand, I do not think it necessary to hold that the granite at the moment of intrusion was everywhere in a state of maximum viscidity. Its condition, I apprehend, varied from point to point; being in some places in the normal condition of a liquefied granite, whilst at others it was almost completely made up of minerals that had already crystallized out of the magma. There were also, we may suppose, numerous gradations between these two conditions. ‘That this was actually the state of the granite I infer from the examination of thin slices under the microscope, and from the appearance of the rock in the field. In some places it is a perfect granite—in others it is a perfect schist. In specimens from some spots the microscope reveals the marks of crushing; in those from other localities these marks are absent. At pages 76-77 of the February, 1587, number of this Macazinr, I have suggested a few reasons to account for a similar state of things in the Lizard gabbro. The rapid, and often apparently capricious, passage of rocks of this class from a granitic to a foliated condition, suggests very complex questions which cannot be dis- cussed in detail on the present occasion; but though I shall not now attempt to explain at length why traction, shear, and pressure, operating on an imperfectly consolidated eruptive rock, fail to produce perfectly uniform results in every portion of the erupted mass, still, it may be as well to briefly allude to some of the causes which, in my opinion, may have produced these results in the Dalbousie granite. One reason has already been alluded to, namely, the want of uniformity in the consistency of all portions of the erupted mass at the moment of eruption. Micro-petrologists are already familiar with the idea that a more or less complete lique- faction of deep-seated igneous rocks takes place when the pressure under which they have been held is relaxed by portions of these rocks finding a vent at the surface ;—instance the partial refusion of the porphyritic quartz crystals in quartz porphyries. The order in which minerals fuse, or crystallize, depends, to mention one factor Col. McMahon—Granite of the Himalayas. 65 only, on pressure; and, in the case of the Himalayan gneissose- granite, pressure must have varied considerably from point to point within the area of eruption. The high probability that the rising granite varied in its con- sistency in different portions of its mass at the time of intrusion must not be lost sight of in dealing with a rock that occurs within an area that extends not for hundreds of feet, or hundreds of yards even, but for hundreds of miles. If other causes besides the absence of perfect homogeneity at the time of intrusion are wanted to account for the variation of structure to be observed in the rock, the following may be mentioned :—At the points where shearing was most severe, secondary heat was probably developed, and the resulting chemical and mineralogical action may have been considerable. Then, again, we cannot suppose that the earth-movements that produced the contortion, overfolding, and faulting of the strata were sudden and explosive in their character; doubtless they were due to long-sustained compression, and the movements that resulted from this compression were repeated— possibly with considerable rests, or intervals between—during long periods of time. Hach of these movements probably left its mark upon the rocks, and who is now to discriminate between the effects of the shear, traction, and pressure that accompanied the actual act of intrusion, and the shear and pressure caused by the earth-move- ments that must, in many cases, have followed the act of injection and have sheared and nipped the gradually cooling granite with a pressure that not only varied locally from place to place, but was applied again and again during successive stages of consolidation ? When I penned the article which appeared in your May, 1887, Number, the object I had chiefly in view was to show that the foliation of the granite of the N.W. Himalayas was due to pressure acting on an imperfectly consolidated intrusive rock prior to its complete con- solidation, and that it was not due to pressure-metamorphism exerted on a solid and cooled rock after it had attained a consolidated and crystalline condition. In short, that it was an incident in the history of the eruption, and was not, like cleavage, due to pressure exerted on a solid rock. The theory of pressure-metamorphism differs materially from the explanation I have advocated to account for the foliation of the granite of the N.W. Himalayas. The former is not concerned with a phase of the consolidation of an eruptive rock. Pressure-metamorphism may come into action whole geological ages after the last stage of the intrusion of an igneous rock has come to an end; and may operate on rocks of purely sedimentary origin. Whether or not pressure-metamorphism applied to solid rocks is capable of producing all the results alleged by the extreme advocates of the theory, is a question foreign to the present inquiry. All that I have contended for is, that, in the regions embraced by my papers, pressure applied to the granite after its complete consolidation was not the cause of its foliation, but rather pressure applied whilst it was yet in a more or less plastic condition. DECADE IlI.—VOL. V.—NO. II. b) 66 Cornish and Kendall—Calcareous Organisms. IV.—On roe MineERALoGicaL ConstituTION OF CALCAREOUS OrGANISMs.? By Vaueuan Cornisu and Percy F. Kenpatt, Berkeley Fellow of the Owens College. Introduction. a. Mr. Sorby’s presidential address at the anniversary meeting of the Geological Society in 1879, attention was drawn to the fact that the carbonate of lime in calcareous organisms is in certain cases in the form of calcite, in others of aragonite, and various genera of such organisms were classed according to their mineralogical con- stitution. It was also shown that aragonite fossils are of greatly inferior stability to those formed of calcite, in many deposits casts only of aragonite fossils being preserved, whilst those of calcite remain unaltered. In the same address Mr. Sorby insisted on the importance of this difference of stability as affecting the trustworthi- ness of the geological record. The idea that the disappearance of aragonite fossils is due to the action of carbonated water naturally suggests itself; at the same time no experimental data appeared to exist which would lead one to suppose that calcite would be acted upon less readily than aragonite by a solution of carbonic acid. Part I. of the present paper contains an account of the experimental evidence obtained as to the cause of the inferior stability of aragonite fossils as compared with those formed of calcite, with observations on the geoloyical conditions favourable to the removal of aragonite fossils. It was pointed out by one of us in a paper in the GroLocicaL Magazine, Nov. 1883, that those shells classed by Mr. Sorby as cal- cite are characterized in the fossil state by a compact texture and by translucency, whilst the aragonite shells are opaque and of a chalky appearance, and the opinion was there stated that these characters would be found sufficiently constant to be of use in determining the zoological position of obscure forms. Part II. of the present paper contains an account of the work done in following out the above observation, and in the examination of certain organisms belonging to groups not yet classified according to their mineralogical constitution. Part J. Two fossil shells, Pecten opercularis (calcite) and Pectunculus glycimeris (aragonite) were selected, not differing greatly in weight, and presenting nearly the same extent of surface. The aragonite shell was a specimen entirely unacted on, with a hard compact surface. These shells were suspended in a solution of carbonic acid, removed. from time to time, weighed, and then placed in a fresh solution of carbonic acid. The experiment was only dis- continued when the aragonite shell fell into fragments. 1 An Abstract of this paper was read before Section C. of the British Association at Manchester, September, 1887. Cornish and Kendall—Calcareous Organisms. 67 Three circumstances were noted, viz. : 1. That the calcite shell lost in weight through solution of its substance, but retained its compact texture and translucency, so that no alteration in appearance could be observed till it had lost a large percentage of its substance. 2. That the aragonite shell lost by solution between two and three times as great a percentage of its weight as was lost by the calcite shell. 3. That the hard compact surface of the aragonite shell speedily disappeared, the shell assuming a consistency similar to that of kaolin, and falling into fragments after losing 60 per cent. of its weight by solution. Experiments with other aragonite shells showed that after a short period of subjection to carbonic acid solution they are reduced to a consistency such that the substance of the shell comes away with a touch, and such that a gentle stream of water is sufficient entirely to disintegrate the shell. Calcite shells, on the other hand, after being acted upon lose only a small quantity of substance by washing. In the Coralline Crag we have observed them in a pulverulent state only in those portions from which the aragonite shells have been entirely removed. From observations 2 and 3 it follows that carbonated water acts so as to decompose aragonite fossils more readily than those formed of calcite, and from 3 it further follows that where water is free to circulate, the aragonite fossils already acted upon lose their coherence and are reduced to the condition of a powder. In addition we see from 1 that the retention of their compact structure and translucency by calcite fossils lends to them an appearance of immunity from the action of carbonic acid which they do not in reality enjoy. It remained to investigate the cause or causes of observation 2, and to ascertain whether the fact observed, viz. that aragonite shells are dissolved far more rapidly than the calcite, is due (a) to difference of mineralogical constitution; (b) to difference of structure of the shell related to that difference of mineralogical constitution ; or (c) to both causes combined. To test the first point we placed pure crystalline calcite and aragonite in fine powder in two flasks of the same capacity and shape together with equal volumes of carbonic acid solution of equal strength, and determined the loss of weight suffered by the substances after the lapse of an equal interval of time in each case. The result of the experiment showed no excess of action on the aragonite over that on the calcite. A similar experiment where finely powdered fossil calcite and aragonite shells were employed gave similar results. The conditions under which these determinations were made were not such as to eliminate certain possible sources of error, but the degree of accuracy obtainable is sufficient to justify us in concluding from the numbers given below that the more rapid solution of aragonite fossil shells is not due directly to difference of miner- alogical constitution, but to difference of structure. 68 Cornish and Kendall—Calcareous Organisms. In the case of the experiment where the fossil shells were sus- pended in carbonated water the percentage of loss is calculated on the weight of the shell before its immersion in the carbonic acid solution in each case, and not on the original weight. It will be observed from the numbers given that the ratio between the losses by solution increases towards the end of the experiment when the aragonite shell had assumed a clayey consistency. Experiment with fossil shells suspended in CO, solution :— Nature deals Loss after After other After other of Subst, Original We. 70 brs. 48 hrs. 74 hrs. Calcite ...... °3196 grams, ... 12°60°/, ... Tl Gaye k Mask 9°44 °/, Aragonite... °3779 ,, Soe 26330 Fie ee, LISIB ORY seen aiorelioag Experiment with fossil shells in a state of fine powder :— Nature of Subst. Original Wt. Loss in Wt. °/, of Loss on Original Wt. Calcite ...... O94 oramsvunnest) WitcOS29)erams..) ss.) 4eD6 Aragonite ... 6010, di "0858, ane 14:27 Experiment with powdered crystals :— Nature of Subst. Original Wt. Loss in Wt. °/, of Loss on Original Wt. Calcite ...... 5850 grams... "0404 grams... 6-90 Aragonite ... SBN T 53 ae 0850 ,, au 5°65 With regard to the question of structure, aragonite fossil shells have a hard surface, but the interior, though close-grained, is porous. The calcite shells on the other hand are compact throughout. The porosity of the aragonite fossils is indicated by the circumstance that they adhere to the tongue. The difference of structure is well shown by the following experiments. If a fossil calcite shell be immersed in water a few large bubbles collect on the shell, and after a time detach themselves one by one. On the other hand, if an aragonite fossil from which the hard outer layer has been removed be immersed, a stream of small bubbles rises rapidly from the shell, giving an appearance of effervescence similar to that produced by the action of a dilute acid on carbonate of lime. The geological conditions favourable to the removal of aragonite shells appear to be: (a) Enclosure in permeable beds. (6) Flow of carbonated water. The latter condition can of course be best complied with above the saturation level of the rock. This is well illustrated by the following observation made at the Coralline Crag pit belonging to Mr. Pettit, on the Leiston road, near-Aldborough, referred to in the paper already cited (Gnot. Mac. Nov. 1883). Here, above the saturation level, aragonite shells have entirely disappeared, casts alone remaining, whilst below the saturation level, in a shallow excavation made in the corner of a small pond, a bed of hard Crag was met with containing actual aragonite shells, though in so advanced a stage of decomposition that it was impossible to secure a specimen. It is interesting to observe that where well-marked lines of flow occurred, even the calcite shells were entirely removed. In the same connection we may quote from Mr. Sorby’s address Cornish and Kendall—Cualeareous Organisms. 69 a passage which has reference to the Portland Oolite. It will be noticed that Mr. Sorby’s conjectures are borne out in detail by our experiments. The passage is as follows: ‘ Where the deposit has taken place in a current, they (the aragonite shells) are more or less completely absent, probably because they had become tender by decomposition and were broken up before final deposition. Under similar circumstances the calcite shells have resisted complete disin- tegration and still show the original structure.” At Walton-on-the-Naze the uppermost beds of fossiliferous Red Crag contain very few calcite shells and immense numbers of aragonite shells. The latter are as a rule greatly decorticated and often quite pulverulent. The overlying bed formerly referred to as “Unproductive Sands” does not as a rule contain any shells, but thin lenticular patches of greatly decomposed fragments of shells occur, the species of which could sometimes, though rarely, be determined. This, and the circumstance that locally pipes of unproductive sand descend into the fossiliferous beds below, show conclusively that this was a case of decalcification. A prior obser- vation by Mr. Whitaker (Q.J.G.S. vol. xxxiii.) led him to the same conclusion. In a Coralline Crag-pit opposite Mr. Chaplin’s farm-house on the road from Dullingham to Sudbourne, very loose sand containing only decomposed calcite shells can be seen to pass up into a loose sandy bed destitute of fossils. Near Sudbourne Church a similar sand occurs, which can be recognised as decalcified crag, by the circumstance that a large per- centage of the sand grains are coprolitic, a character which distinguishes the Red and Coralline Crag from all other deposits. In the classical pit in Sudbourne Church Walks (Mrs. Rackham’s), where the superposition of Red upon Coralline Crag can be observed, the Coralline Crag has suffered the removal of its aragonite shells, while the overlying Red Crag contains a profusion of organisms of aragonite constitution, a fact which appears to indicate that, previously to the deposition of the Red, the Coralline Crag had stood above the sea-level and had undergone submergence. Part II. As stated by Mr. Sorby, the true mineralogical character of any calcareous organism is best indicated by the specific gravity. This was determined by Mr. Sorby from the powdered substance. We were desirous, however, to ascertain if the destruction of the specimens could be avoided ; and the following numbers from our determinations by the method of suspension show that in many cases at least it is not necessary to sacrifice the specimen. In the case of univalve shells, however, it is sometimes necessary to break into the whorls. Where a recent specimen has a thick epidermis, this must be removed by caustic soda. The observations which follow were made in following out the indications obtained :—1. from the known inferior stability of arago- nite fossils; 2. from the rule which appeared to hold with regard 70 Cornish and Kendall—Calcareous Organisms. to the translucency of calcite fossils and the opacity of those of aragonite. Nature of Specimen. Weight of Specimen. Sp. gr. Crystal of aragonite hexagonal (twin form)............ 37°3560 grams ... 2°933 Avragonite, fibrous variety ja-nveseseceeseceseccssonscess 23°5111_ ,, wee =2°857 Artemis lentiformis (fossil, opaque) ..........sceeeeeeees 4°7490 ,, ... 2 840 Pectunculus glycimeris (TeCENt) ........ececenecececeeeeees 3°9445,, ws (2°840 Calcite (cleavage rhombohedron) ...............2ceeeeeee S022) hes, see o2rallO Pecten opercularis (fossil, translucent) ...............068 18 (Mle Bodh. RAW) Pecten opercularis, (LECENt) .......secesecasserecnseoosee Tey, 5 ve 2°70 GASTEROPODA. Scalaria, to which reference was made in the paper before quoted, proves to be calcite, as suggested from its translucency and mode of occurrence in the Coralline Crag. Its specific gravity is 2-685. Murex tortuosus has a thick opaque inner layer, while the invest- ment constituting the frills or varices is translucent. The specific gravity 2°85 indicates that the greater part of the shell is aragonite, as suggested by its appearance. We are disposed to regard these features as valuable in the deter- mination of the true affinities of the so-called Purpura tetragona, regarding which the late Dr. Jeffreys and Mr. Searles V. Wood jun., were at issue. Purpura as typified by P. /apillus has an extremely thin opaque layer, which does not reach the edge of the outer lip, and the specific gravity corresponds with that of calcite shells. P. tetragona on the other hand is opaque, with a translucent layer so insignificant in thickness that it is removed by attrition from all the prominences. The translucent layer is not visible within the outer lip. The affinities of P. tetragona are therefore probably with Murex arenaceus rather than with P. lapillus. Tectura testudinaria. Sp. gr. of recent specimen 2°834. In the fossil state it is opaque, with a translucent outer layer, hence we may conclude that, as in the case of M. tortuosus, the inner layer is aragonite and the outer calcite. Fusvs. This genus furnishes evidence, which we consider to be conclusive, respecting the determination of the constitution of calcareous shells by their opacity or translucency in the fossil state. Mr. Sorby stated in his address that the inner layer of usus, as typified by F’. antiquus, is aragonite, the outer calcite,.and in the paper by one of us already cited it was mentioned that the inner layer was opaque and the outer translucent, and several fossil species were instanced, which, being entirely opaque, were probably wholly aragonite. The sp. gr. of three species which have been determined by us shows them to be wholly aragonite. We give the sp. gr. of F. antiquus for comparison. F. ANUIQUuus vo ccccccerceceeee . sp. gr. 2°668 (very thin aragonite layer) TH GOSBOICP * posanveeeonboaca0l A 2°88 LOS SIPGTED MOOS: Gadonouebescen AA 2°95 Fr. longevus ...... po0eednab080 ap 2°89 Cornish and Kendall—Caleareous Organisms. ma. The exceptionally high sp. gr. of / pyriformis is no doubt to be accounted for by the fact that the specimen was impregnated with oxide of iron. CEPHALOPODA. Ammonites—From the mode of occurrence of these shells, the circumstance that in porous beds casts only are preserved, and the similarity in appearance of the shells to those of Mautilus (deter- mined by Mr. Sorby to be aragonite), we are justified in assigning them to the aragonite division. The Aptychi, however, have the translucency characteristic of calcite, and they are found well preserved in beds such as the Chalk, in which the Ammonites are only represented by casts. The determination of the sp. gr. 2°70 shows them to be calcite. Belemnites.—We find in Woodward’s Manual of Conchology, p. 1738, that according to the determination of Mr. Alex. Williams, the sp. gr. of the guard of Belemnites puzosianus is 2°674, and that of Belem- nitella mucronata 2-677; they are therefore calcite, as their trans- lucent appearance, familiar to all geologists, would lead one to suppose. The phragmacone of Belemnitella is not known, and as no aragonite shells are preserved in the Upper Chalk, we were led to believe that the phragmacones of Belemnites would prove to be aragonite. Mr. Robert Etheridge kindly furnished us with a specimen in which the chambers were filled with translucent calcite, while the septa and the siphuncle which were preserved presented the usual chalky appear- ance of aragonite. The specific gravity was found to be 2°75, justifying the belief that a small quantity of aragonite was present, with the greater certainty that the appearance of the specimen shows it to be free from oxide of iron, and the mode of deposition of the calcite in the chambers, together with its high degree of translucency, furnish guarantees of its purity. A specimen of B. minimus from the Gault has the phragmacone preserved, and it presents the appearance characteristic of aragonite. It may be of interest here to note that the homologous structure of sepia has been determined by Sorby to be aragonite. PoLYPLACOPHORA. Chiton (recent), sp. gr. 2°848, therefore aragonite. HETEROPODA. Dolabella (recent), sp. gr. 2°859, therefore aragonite. LAMELLIBRANCHIATA. Pecten opercularis (recent), sp. gr. 2°70, therefore calcite. Pectunculus glycimeris (recent), sp. gr. 2°845, therefore aragonite. Artemis lentiformis (fossil), sp. gr. 2°84, therefore aragonite. Teredo Norvegica.—Teredo is regarded by Dr. Sorby as a typical calcite shell: but certain tubular fossils found by one of us in the Crag, and which have been regarded as T. Norvegica, have the opacity characteristic of aragonite; and upon this circumstance and peculiarities in its mode of occurrence the opinion was based that the 72 Cornish and Kendall—Calcareous Organisms. reference of the form to Teredo had been erroneous. In this view the late Dr. Gwyn Jeffreys concurred. The fossil has a sp. gr. of 2-9, and is therefore composed of aragonite. We offer no suggestion as to its affinities. HExaAcoRALLA. All those corals examined by Mr. Sorby consisted entirely or almost entirely of aragonite. Parasmilia centralis.—The circumstances of the preservation of this coral in the Upper Chalk induced us to examine it, when we found that it was translucent, and therefore probably calcite. ‘This conclusion is confirmed by the sp. gr. 2°70. Ponyzoa. Mr. Sorby observes that many Polyzoa have a specific gravity intermediate between those of calcite and aragonite, and suggests that they may be composed of a mixture of calcite and aragonite. Observations by one of us on Polyzoa show that these two substances, as indicated by the translucency and opacity, are not actually inter- mingled, but, as we have found to be invariably the case in other organisms, occur as two distinct layers, inasmuch as many genera, such as Eschara, have, when well preserved, an outer opaque and an inner translucent layer, the former being absent in deposits from which the aragonite shells have disappeared. Here the disposition of the layers is the reverse of what is found in the Mollusca, which always have the aragonite layer internal. FoRAMINIFERA. Mr. Sorby has ascertained that certain of these (genera not speci- fied) are composed of calcite, but the facts we have accumulated regarding the group show that one great family, the Porcellanea, is similar in occurrence and behaviour to those structures characterized by the possession of aragonite tests. Moreover, the aspects of the tests, which have suggested the names Vitrea and Porcellanea, are as well shown in the fossil as in the recent state, and agree exactly with the aspect of calcite and aragonite shells respectively. Although we have not yet direct experimental proof that the Porcellanea con- sist of aragonite, yet it will be seen from what follows that they have been shown to be, relatively to the Vitrea, unstable towards the action of carbonated water. The form called Biloculina ringens occurs along with aragonite shells in the Coralline Crag of Gedgrave, and is the most abundant Foraminifer in that deposit; but at Aldeburgh, Iken, Sudbourne Cross Roads (Mrs. Sewell’s Pit), and the White Gates Pit, Sud- bourne Park (in the Coralline Crag from which the aragonite shells have been removed), there is not a trace of it; while the Poly- morphina frondiformis, comparatively rare at Gedgrave, is found here well preserved. In Prof. King’s “ Monograph on the Permian Fossils” (Palzont. Soc. vol. ii.) it is stated that no Imperforata Foraminifera are known from any formation below the Trias; but the most striking evidence Cornish and Kendall—Calcareous Organisms. 73 of the instability of Porcellanea is furnished by the list of Chalk Foraminifera in Dixon’s ‘‘ Geology of Sussex,” of which an analysis is subjoined. CuaLk ForaMINIFERA. EUGTLOLA ESD eRTALOW trasescteeadecsoetetcicescccasissceesisanosenes Porcellanea. SUILULOUCICM ANS DD eirsconicseacieeceeneerias cranes csieoseessiss ses Arenaced, LLG ERO, CRYESINS: sopodosd0a0 ¢ 356d00 008s a0aR EKO CoEaCObOEACUGCOONC Vitrea. Roliymonphinid@, 4 spp. AW VATS.. se. .ccce-enuececsesseseoree Ay JBN SOA UCE, MESS) Ns enogon cod coaGe Coe HOON COM DECCODBODECORCOEOE 70 PRES UALONUA Ea OUSD Der seer cctceiseccnessnaceleseescecm sess. sacle 5 GHODUGETINGPOVSPD Wosachraacsestoueandentlltore veer cared «dese 0 TOU CIITA reepb a She orig de BOO ETOCS Cc ORC BOE RCOC LOS CCR OSE CCRRe nee aeEeE 5 The significant fact appears from this that in a deposit from which all the aragonite shells have been removed, among 93 specimens of Foraminifera recorded, only one porcellanous form is included, and that presumably in so bad a state of preservation as to forbid specific determination. Judging from the analogy of recent Foraminiferal deposits from all depths, the Chalk should have contained originally a considerable proportion of porcellanous species. The chain of evidence was, however, less complete than in the case of larger structures, where casts nr replacements have been observed. We therefore tried the action of a solution of carbonic acid on Miliola (porcellanous) and Rotalia (vitreous) in the fossil state, with the result that the porcellanous species was reduced to a condition in which it was disintegrated by a stream of water, whilst the vitreous species maintained its integrity, neither did it lose its translucency or compact structure. It may be added that the strength of structure of the porcellanous is at least equal to that of the vitreous species. From experiment and observation we may therefore infer that Porcellanea are of inferior stability to Vitrea in presence of carbonated water, and consequently that their absence from a formation such as the Chalk does not warrant the assumption of their non-existence at the period of its deposition. Note.—Subsequently to the reading of the paper our attention was drawn to a communication by Prof. Sollas (Proc. Roy. Soc. Dublin, vol. iv. new series, 1885), in which the author comments on the rarity of Imperforate Foraminifera in the older rocks. The specific gravities were determined in the Sondstadt solution. The values obtained for recent specimens were Vitrea 2°626 to 2674, Porcellanea mostly 2°7, but ranging to 2°722. Wealso have succeeded in obtain- ing sufficient recent Spiroloculina for determination by the specific gravity bottle in a state of fine powder. Two experiments gave respectively 2°70 and 2°71. As we have not yet completed our examination of this group, and the percentage of animal matter has not yet been determined, we express no opinion regarding the mineralogical constitution of the tests, but content ourselves with pointing out that, as in the case of aragonite organisins, opacity in the fossil state accompanies instability towards carbonated water, both probably being related to the structure of the shell. 74 Fox and Somervail—Porphyritic Rocks of the Lizard. V.—On THE OccuRRENCE oF PorpHyritic STRUCTURE IN SOME Rocks or tHe Lizarp Dtisrrict.! By Howarp Fox, of Falmouth, and Avex. Somervatt, of Torquay. EING the fortunate possessors of Prof. Bonney’s valuable papers ? on the Lizard Serpentines and Schists in a pamphlet form, we examined the coast this spring somewhat minutely from Polurrian Cove on the west to the Blackhead on the east of the Lizard Point. We had tracings of the entire coast in our pockets, taken from the 25 inch Parish Maps, and owing to fine weather, and a favourable state of the coast, we were able to visit some of the less accessible rocks, and to trace some beds which at times are covered with sea- weed and shingle or débris from the falling cliffs. Prof. Bonney’s porphyritic diabase had been previously identified by one of us after along search over the 18 acres of rocks and boulders exposed at Polpeor at low-water spring-tides. We made ourselves familiar with this rock, and were thereby enabled not only to trace it further, but to recognize a porphyritic structure in many dykes and intrusions along the coast, and also in the darker bands of Prof. Bonney’s “ Granulitic Group.” Commencing at Polurrian, the most westerly point, we will proceed eastward, noting the chief localities where the porphyritic structure may most readily be observed. Ve tian Heap. —About 250 yards N.W. of the granitic vein marked on the Ordnance Map, near the base of the cliff and opposite an island, some narrow porphyritic dykes occur in the midst of bands of disintegrated serpentine, steatite, etc., and quartzose rock. Goop GastoL (?).—At the inner end of a little cove about 800 yards §.E. of Oliver’s Refreshment Room at Kynance Cove there are some dykes with a few crystals of felspar scattered through their compact dark matrix. Hoxzestrow.—On the foreshore at the southern end of this land slip and a little N.W. of Pentreath Beach are several masses of banded crystalline rocks in situ resembling the ‘ Granulitic Group.” In these rocks may be discovered by careful search felspar crystals scattered through the matrix of the darker bands. PrenrreatH Bracn.—At the extreme north end of this beach a granitic vein runs up the cliff. Adjoining are some trap dykes also cutting the serpentine. About 100 yards south of this point a por- phyritic dyke may be seen at low-water running in a N.W. and S.E. direction. This dyke is again found in a chine in the cliff in a line with its strike. At the south end of this beach occurs the junction of the serpentine with hornblende schist. About 100 yards south of this junction we find indications of porphyritic structure in the massive cliffs, here chiefly composed 1 An Abstract of this paper was read before the British Association, Section C. (Geology), Manchester, September 1887. * Quart. Journ. Geol. Soc. Noy. 1877, pp. 884-928, and Feb. 1888, pp. 1-24. Fox and Somervail—Porphyritic Rocks of the Lizard. 75 of micaceous schists. These indications continue for the next 3800 yards, viz. to considerably south of Caerthillian, and on the foreshore are seen stones and boulders of typical porphyritic structure. Norru Carrtut~yran.—The most readily accessible place where a typical porphyritic rock may be seen in situ is immediately N.E. of the headland which bounds Caerthillian on the north. This spot can be reached with ordinary care from the top of the cliff, which is lower here than on either side. A quartzo-felspathic rock is exposed close under the soil, and a few yards below it are several bands alternating of porphyritic and granulitic rock much faulted. The darker bands are thickly studded with small well-defined crys- tals of felspar, which on the weathered surface project beyond the matrix. These bands can be traced for 20 yards in a N.W. and §.E. direction, much twisted. They extend in a §.W. direction to high-water mark and down the cleft to the south. SourH CaERTHILLIAN.—Some rocks apparently in situ on the fore- shore 70 to 100 yards south of Caerthillian Cove show crystals of felspar in their soft micaceous matrix. The adjoining cliffs show a porphyritic structure in a more compact rock. Pistrt Oco.—Rounding the Lizard Head, we can descend the cliff at this place, where we find a greenish porphyritic rock running N.W. and §.E., and 200 yards further east we reach the most southern point. Potrror.—When the shingle and seaweed have sufficiently left the coast, the porphyritic diabase discovered by Prof. Bonney can be traced running N.W. and §.H. for 150 to 200 yards. It is exposed in the micaceous and hornblendic schists in an intricate manner, appear- ing again and again at and near the base of the cliff and on the fore- shore both in Polpeor and the adjoining cove to the N.W. It can be traced in the mass of rock which at half-tide forms the eastern boundary of Polpeor beach, and through this on the foreshore still further east towards Polpeor Island. It appears again in Vellan Drang 200 yards 8.W. of Polpeor Cove in the strike of the Pistil Ogo Beds. Parn Vooss (locally Penvosz).—This cove directly north of the Balk Quarry is the place at which Prof. Bonney’s “ Granulitic Group” sets in, and continues with alternations of hornblende schist and serpentine to Kennack Beach. Here also the gabbros appear in mass, and here the porphyritic structure in the dark bands of this crystalline series may be seen to advantage. The foreshore is strewn with boulders recently fallen from the cliff, and the crystals of felspar in some of these are from one to two inches long and almost as broad. The same occurrence of crystals is seen in the cliffs, but not to such advantage as in the boulders. Potparrow.—Proceeding still eastward past Lean Water and Gothan Point or Whale Rock, we come to Polbarrow, and can trace porphyritic indications throughout this region. Kinrpown.—LHast of Cadgwith we also find crystals and felspar in the dark bands of the granulitic group. 76 ~=Fox and Somervail—Porphyritic Rocks of the Lizard. Carrieon.—Here Prof. Bonney’s porphyritic dyke’ is seen about 100 yards south of the Poltesco Serpentine Factory. Passing Caerleon Cove, we climb up the hill by the Coast-guard path, cross the rocky slope above “ Little Cove,” and scramble down into the next small cove north of a projecting serpentine headland called in the Parish Map Polbream Point. Here we find rocks with large crysials of felspar, both in situ and in boulders scattered over the rocky foreshore for the next 300 yards northward. Cavouca.—The Parish Map gives the name of Cavouga to the serpentine rocks running out to sea 100 yards north of Polbream Point, and as the rocks containing large crystals of felspar occur on each side of these serpentine rocks, it may be an appropriate name by which to designate this region. There are two exposures of these large-crystalled porphyries in situ at the foot of the cliffs; the first about 90 yards S.W. of Cavouga Rocks, the second about 200 yards north of them, or say 600 yards N.E. of Poltesco Serpentine Factory. The first of these appears to cut the serpentine, and can be traced up the cliff, the darker bands containing both large and small crystals of felspar at various angles, and the associated lighter bands resembling the quartzo-felspathic bands of the ‘‘Granulitic Group.” The second exposure north of Cavouga Rocks resembles three dykes cutting through the serpentine; but, as Colonel MacMahon suggests, it may be one dyke which by pressure has been doubled up on itself. Between and on either side of these two exposures the darker bands of this crystalline series of rocks show from time to time distinct crystals of felspar in the massive rocks as well as in those which appear to cut the serpentine as dykes. On the foreshore are many boulders so studded with crystals as to resemble mosaic, the crystals occasionally reaching a length of nearly six inches and a breadth of from two to three inches. One boulder had some of the crystals beautifully tinted with red. Kennacx.—In proceeding east to Kennack, we trace the crystals in the dark bands of the granulitic group, and on reaching the beach we find the porphyritic structure very marked in some isolated masses of the same group, one of which Prof. Sedgwick described as a “ Green- stone porphyry.” * North of these in a low cliff we trace a similar structure. GREEN SappLE.—About 500 yards E.S.E. of the thatched shed at the extreme east of Kennack Beach there is another exposure of rock with large crystals of felspar resembling a dyke cutting the serpentine. The foreshore is here also strewn with boulders of porphyritic rock. Summary. The crystals of felspar are found to be most numerous in those rocks which lie in the closest proximity to the gabbro and serpentine ; 1 Quart. Journ. Geol. Soc. Nov. 1877, p. 900. * Trans. Cambridge Phil. Soc. vol. i. p. 18. Rev. N. Glass—The Spirals of the Brachiopoda. 77 they have their long axis at various angles, and are mostly small, except at Parn Voose, Cavouga, and Green Saddle. The felspathic and hornblendic lines often circle round the crystals. Such is a brief statement of the bare facts of our observations in this particular direction. Without discussing any theory as to the true nature and origin of the whole of the schists, we think that _ the porphyritic structure, so prevalent in the dark bands of the “ Granulitic Group,” in many of the micaceous and other rocks, as also in the later intrusions cutting the serpentine, indicates an igneous origin for many rocks hitherto regarded as schists. VI.—On tHe Prinorpat Mopirications oF THE SPIRALS IN THE Fosstn BracHIopopa. By the Rev. Norman Guass. R. DAVIDSON, assisted by the writer, gave a provisional sketch of the classification of the spiral-bearing Brachiopoda in the volume of the Paleontographical Society for 1883." As Dr. Davidson then said, our design was “to assist those paleontologists who might feel inclined to continue the subject.” The following notes have been written by me for the same end, and I think that if they are carefully read and compared with the figures in Dr. Davidson’s Carboniferous, Devonian, and Silurian Supplements, they will give a tolerably clear idea to the student of a very complex and difficult subject. I have perhaps some claim to write upon this subject from the years of close and continuous investigation which I have devoted to it, and from the fact that I have discovered a large proportion of what is now known concerning the spirals and their connections. In the “ Geologist,” 1858 (vol. i. pp. 457-473, folding plate xii.), Dr. Davidson gave figures and descriptions of all that was known up ~ to that date concerning the spirals and their connections. The com- parison between these figures and those given in his Carboniferous, Devonian, and Silurian Supplements in 1880 and 1882 is very remarkable as showing how recent have been the great majority of the discoveries in this interesting group. I have thought, therefore, that it might add to the interest of my notes if I gave in each case the date of the discovery and the name of the discoverer, that is, so far as these are known. Of course it will be understood that there are many genera and species which have the same internal characters as to the position of the spirals, their attachments to the hinge-plate, 1 Anticipating a delay of fifteen months, owing to the retarded appearance of his Monograph in the Paleeontographical Volume, the veteran author on the brachiopoda, Dr. Davidson, published the result of his labours, in association with the Rey. Norman Glass, concerning the calcareous spirals of the Paleozoic Brachiopoda, in the Grotocicat Macazine for 1881 (Decade II. Vol. VIII. pp. 1, 100, 145, and 289), illustrated by Plate V. and fourteen Woodcuts. It will be well for the reader to refer to these articles, as the figures therein given more fully elucidate the present paper, and the whole subject is treated in greater detail by Dr. Davidson; save and except the additional remarks made by Mr. Glass herein, which refer to discoveries of a later date than 1881.—Ep. Grou. Mae. 78 Rev. N. Glass—The Spirals of the Brachiopoda. and their connections with each other, but only the first discovered example will be given of each distinct and peculiar form. The names and dates given in brackets refer in each case simply to the discovery of the calcareous spirals. Tue Positron oF THE SPIRALS IN THE SHELL. In the Spiriferide the spirals have their bases facing each other in the centre of the shell, but usually their apices have a more or less upward direction towards the posterior angle of the lateral margins of the shell. This upward direction is very marked in Spirifera lineata, var. imbricata. The spirals are sometimes directed backwards into the rostral cavity of the ventral valve as well as upwards, for example in Oyrtina heteroclita. In all the other families or groups of the spiral-bearing Brachio- poda the spirals are always so disposed as that a transverse section taken through the greatest circumference of the shell would as nearly as possible pass through the apices of the two spirals and the centre of their respective bases. The spirals which are thus arranged in the shell have, so far as has been ascertained, six different positions in the various genera to which they belong. Supposing that the dorsal or lesser valve in a specimen of Athyris has been removed, the spirals will then appear with their bases facing each other in the centre of the shell, and their apices directed towards the lateral margins of the shell. The five remaining positions of the spirals referred to might all be obtained by rotating the spirals simultaneously each on its own axis—that is, its perpen- dicular axis, from the posterior to the anterior border of the spiral. (Of course this could not be done in the specimen itself, but the motion might be illustrated by two cones cut out in wood.) Thus, in the case of Athyris as described above, if the two spirals were rotated simultaneously outwards each on its own perpendicular axis, that is, the right-hand spiral to the right and the left-hand spiral to the left, the spirals would soon assume the position in the shell and towards each other of the genus Dayia, Dav. (Glass, 1880), in which the apices of the spirals face the middle of the lateral portions of the ventral valve. Continuing the rotation Thecospira (Zugmayer, 1880) is reached, in which the apices of the spirals face the bottom of the ventral valve. Again continuing the rotation we have succes- sively Glassia, Davidson, 1881, in which the apices of the spirals face each other in the centre of the shell, Zygospira, Hall (Whitfield, 1862), in which the apices of the spirals are directed obliquely into the cavity of the dorsal valve, and Aétrypa, in which the apices of the spirals face the bottom of the dorsal valve. And a still further rotation would bring the apices of the spirals to their first position as in Athyris. Tue ATTACHMENTS OF THE SPIRALS TO THE HINGE-PLATE OF THE Dorsat VALVE. There is not much variety here. In the Spiriferide the attach- ments are straight. In the Nucleospiride and Athyride, and in Rev. N. Glass—The Spirals of the Brachiopoda. 79 Hindella, belonging to the Anazygida, the primary lamellz shortly after attachment to the hinge-plate are bent backwards towards the ventral valve, each lamella forming an acute angle with the com- mencement of the first convolution of the spiral (this attachment was discovered by Davidson in 1858). In Nueleospira, Hall, and Athyris, M‘Coy (Glass, 1882), this angle is bent or curved under like a beak. In some American species of Athyris, M‘Coy (Whitfield, 1859), the angle is not acute, but more open and loop-like. In Atrypide and Anazygide the primary lamelle shortly after attach- ment to the hinge-plate are bent outwards towards the lateral margins of the shell. Tue Loop, or THE CoNNECTIONS OF THE SPIRALS WITH EACH OTHER. In the Spiriferide the principal character is the straight attach- ment of the spirals to the hinge-plate. In Spirifera (Davidson, 1858) the loop is imperfect, consisting of two internal processes, arising from the primary lamellz, and directed downwards between the spirals, but not uniting. In Cyrtina, Dav. (Glass, 1882), these pro- cesses unite at an acute angle. In Spiriferina, D’Orb. (Davidson, 1851), the loop consists of a straight or curved horizontal band almost on a level with the dorsal surface of the spirals. In the Atrypide the principal character is the position of the loop exterior to and above the spirals. The loop is directed down- wards, and is simple and rounded (Whitfield says that in some examples of Atrypa the loop is acutely angular—this had never been observed, however, by Dr. Davidson or myself). In Atrypa, M‘Coy (Whitfield, 1866), the loop is small, in Zygospira, Hall (Whitfield, 1862), it is much wider, and lower down, and curves upwards towards the hinge. In the Anazygide the principal character is the position of the loop rising from the bottom of the spirals. In Anazyga (Glass, 1882) the loop is simple and rounded, and exterior to the spirals. In Hindella, Dav. (Glass, 1882), the loop is ‘simple and rounded, with a short spinous extremity, and interior to the spirals. In Dayia, Day. (Glass, 1880), the loop is simple and angular, with a short spinous extremity, and it is placed between the primary lamellee on the dorsal side of the spirals. In the Nucleospiride the principal character is the presence of a simple loop, more or less angular, between and near the centre of the spirals, and directed almost horizontally from the dorsal to the ventral side of the spirals—for example, Nucleospira, Hall (Whitfield, 1859). In the Athyridg the principal character is the presence of an internal loop more complex than that of the Nucleospiride, and extending upwards from the centre of the spirals. The loop of the Athyrid@ is really an extension in an upward direction of the simple loop of the Nucleospiride. In Bifida, Dav. (Glass, 1882), there isa small bifurcation at the end of the simple loop. In Whitfieldia, Dav. (Glass, 1881), the loop is extended further upwards than in Bifida by a rather long single process, which occurs between the simple loop 80 Rev. N. Glass—The Spirals of the Brachiopoda. and the bifurcation. In Meristella, Hall (Whitfield, 1860), each side of the bifurcation at the end of the simple loop curves round upon itself so as to form a ring. This loop, which thus contains two rings, occurs also in Merista. In Athyris, M‘Coy (Davidson, 1858), there is a roof-like expansion at the end of the simple loop, from the top of which two accessory lamellz curve upwards and backwards to the inside of the primary lamelle, and are continued downwards to the ~ centre of the spirals on the dorsal side. In Kayseria, Dav. (Glass, 1882), at the end of the simple loop there is a single rounded process, and at the end of this process the loop bifurcates in an upward direc- tion, as in Athyris. The accessory lamella, however, do not terminate as in Athyris, but are continued between the main coils to the end of the spirals. Thus there are fourteen forms of loop known, most of which have been recently discovered. Dr. Waagen describes the interior of the genus Eumetria. He says, ‘The primary lamellz are very strange in their development. They show broad wing-like expansions at their origin, which are sometimes very strongly developed.” This “ very strange” develop- ment had been previously worked out by me, and figured by Davidson in 1881 as existing in Athyris plano-sulcata,! in which the primary lamelle near their origin increase in width—the increased width extending downwards nearly to the centre of the spirals on the dorsal side. Dr. Waagen gives a description of the loop of Eumetria, and it seems to be similar to the simple loop of the Nucleospiride, with the exception that the loop commences nearer to the origin of the primary lamella, and has a downward direction between the spirals. Supposing this to be correct, the loop of Eumetria forms an addition to the number of loops previously worked out. Davidson gives two figures of the loop of Uncites? in his Devonian Supplement, 1882. From these figures the loop would seem to be simple and transverse as in Spiriferina, with the excep- tion that there is a thickening at the centre of the loop, which on the upper side amounts to a short spinous projection. ‘The attach- ments to the hinge-plate are straight, as in the Spiriferide. With the exception of the spirals in Thecospira, and the loops in Spiriferina, Humetria, and Uncites, all the particulars given above have been carefully verified by my own preparations. P.S.—I have made no reference in the above article to the eminent Paleontologists by whom the respective genera were determined and described. The discoveries of Mr. Whitfield were described by Prof. Hall, of Albany, U.S. My own were described by Dr. Davidson, whose recognition of any assistance I may have rendered him in his great work was always most generously made. (As see Grot. Mae. 1881, loc. cit.) 1 See Groz. Mae. 1881, Dec. II. Vol. VIII. p. 5, Figs. 2 and 3. 2 See Grou. Mac. 1881, Dec. II. Vol. VIII. p. 153, Figs. 20 and 21. Dr. R. H. Traquair—Carboniferous Selachii. 81 VII.—Norers on Carsonirerous Sexnacutt.! By Dr. R. H. Traquair, F.R.S., F.G.S. The Cladodontide. HE teeth known as Cladodus (type ©. mirabilis, Ag.) have a flattened, transversely elongated, sub-elliptical or reniform base, the anterior margin being straighter than the posterior and often shghtly excavated in the middle. Anteriorly the base is thick, and generally shows a groove separating the truly basal from the coronal portion, while the posterior margin is thin owing to the downward and backward slope of the upper surface. From this upper surface anteriorly spring a number of cones or denticles, of which the median is the longest; it is flanked by lateral denticles, of which an outer one on each side is longer than those intermediate. The larger denticles, at least, are flattened antero-posteriorly and have lateral cutting margins. There are two exceedingly well-marked species of common occurrence in the British and Ivish Carboniferous Limestone, namely, C. mirabilis, Ag., and C. striatus, Ag. C. marginatus, Ag., I also believe to be a good species, as well as C. Milleri, Ag. On C. acutus, Ag., conicus, Ag., basalis, Ag., Hibberti, Ag., and parvus, Ag., I offer no opinion, not having seen the types ; but as to the new species added by Mr. J. W. Davis in his large work on the fossil fishes of the Carboniferous Limestone series of Great Britain” there is scarcely one which will stand the test of careful comparison with the common species described by Agassiz. C. Hornet, Dav., C. elongatus, Dav., and C. curtus, Dav., are in my opinion simply synonyms of C. striatus, Ag.,— C. mucronatus, Dav., and destructor, Davis, of C. mirabilis, Ag. It is rather difficult to give any opinion upon C. curvus, Davis. In the Edinburgh Museum, and in the Collection of the Geological Survey of Scotland, there are a few teeth of what is evidently a new species of Cladodus, from the Lower Carboniferous rocks of Eskdale in Dumfriesshire, though I refrain on the present occasion from giving ita name. In these teeth the surface of the cones is perfectly smooth and glossy, and in the absence of striations they approach C. van Hornet and prenuntius of St. John and Worthen. The thought has struck me, is it possible that this undoubted Cladodus may repre- sent the dentition of Ctenacanthus costellatus, the unique specimen of which, with the spines in situ, occurred in the same beds? It will be recollected that the only tooth visible in the specimen of Ctena- canthus costellatus was an imperfect one, but its one visible cusp was smooth. If there is any connection here, the specimen of Ct. costel- latus must have been a young individual, as these teeth indicate a fish of much larger size. This brings up once more tbe question of the correlation of Cladodus and Ctenacanthus, a question which I must admit is still involved in great obscurity. When I wrote my description of Read before the Royal Physical Society of Edinburgh, 18th January, 1888. 2 Trans. Roy. Dub. Soc. 1883. DECADE III.—VOL. V.—NO. II. 6 82 Dr. R. H. Traquair—Carboniferous Selachii. Ctenacanthus costellatus,’ I was inclined to believe that Ctenacanthus and Cladodus represented the spines and teeth of the same genus, and that the genus itself was Hybodont. Mr. Garman, however, in his paper on Chlamydoselachus disputes that view, and claims that remarkable recent shark which has only one dorsal fin and no spines at all—a form placed by Dr. Giinther in the family Notidanida—to be the modern representative of the ancient Cladodonts. It is perfectly true that the small teeth towards the angles of the mouth in Chlamydoselachus when seen from the front strongly resemble those of Cladodus, yet this resemblance is not very apparent in those which cover the greater part of the jaws, while the bases of the teeth are to my eye strikingly dissimilar. I cannot therefore, without further evidence, accept Mr. Garman’s very confident assertion that Chlamydoselachus is a Cladodont, leading as it does to the inference that Cladodus had no dorsal spines. That Cladodus at all events is not quite so close to Chlamydoselachus as Mr. Garman believes is, I think, fully shown by a remarkable specimen from the Carboniferous Limestone of East Kilbride, Lanarkshire, which has been lent to me for description by its possessor, Mr. James Neilson, of Glasgow.? This specimen was recovered from the quarry in separate pieces by the late Mr. A. Patton, who, I understand, did not feel sure that they all belonged to the same specimen. However, the fragments were pieced together by Mr. Neilson, and after a most careful scrutiny of the whole, I have come to the conclusion that the fragments do belong to the same specimen and are rightly arranged. We have first a head, compressed from above downwards, whose jaws are crowded with truly cladodont teeth of the type of C. mirabilis, though apparently belonging to a hitherto undescribed species. This is followed by a mass of crushed and inextricably confused cartilages representing the branchial apparatus, and then come two scapulo-coracoids, each with a pectoral fin attached. The fin of the right side is the better preserved, and shows first a number of elongated radial pieces whose bases, separated from the rest by joints, are attached directly to the shoulder-girdle and evidently represent the propterygium and metapterygium of ordinary Selachii. Behind these is an oblong metapterygium bearing radials preaxially, whose anterior portion seems to have absorbed the bases of one or two adjacent radials, but whose posterior extremity is con- tinued backwards as a long narrow segmented stem consisting of nine rectangular joints, and reminding one at first sight of a vertebral column! This part in both fins is cut off by the edge of the stone, so that its actual length and number of segments are not seen. Some small radials are seen attached to the preaxial side of the first two segments,—none on the others, or on the postaxial side of the stem. The interest of this specimen is extreme, as it is at least capable of bearing the interpretation that we have here a veritable uniserial 1 Grou. Maa. Jan. 1884, pp. 3-8. 2 As I have promised to ‘lay a detailed description of this specimen before the Geological Society of Glasgow, I can only make a few general remarks upon it in the present instance. Dr. R. H. Traquair—Carboniferous Selachii. 83 archipterygium, intermediate between the truly biserial one of Xenacanthus and the pectoral fins of ordinary sharks. If this inter- pretation is correct, then, along with Xenacanthus, this specimen is a witness against the lateral fold theory of the paired fins, at present so popular with anatomists and embryologists. Into that question I shall enter on another occasion, meanwhile so much is clear, that if we have before us the pectoral fin of Cladodus, and I do not doubt that we have, the affinity between that genus and Chlamydoselachus is not quite so close as Mr. Garman maintains, seeing that in his fish the pectoral fin shows the ordinary arrangement of basal pieces, though the metapterygium has two segments. What then of the Ctenacanthus theory ? No spine is seen in con- nection with the Hast Kilbride Cladodus, but as the body is absent, Spines may have been borne by the fish when complete. Again, in the Eskdale Ctenacanthus the form and structure of the pectoral fin are not shown, and though I interpreted its one imperfect tooth as “‘Cladodont,” I am willing to leave that an open question. It may be hybodont, and the hybodont form with its vertically com- pressed base must not be confounded with the cladodont type with its base horizontally flattened and irregularly elliptical or reniform. And in one of the instances which have been advanced to prove the connection of Cladodus with Ctenacanthus, a mistake has certainly been made. So far as I have seen them, the teeth which are found associated with the Coal-Measure Cienacanthus hybodoides, Eg., do not belong to Cladodus mirabilis, Ag., as has been asserted, but are allied to Hybodus in their narrow, compressed non-expanded bases. Mr. J. W. Barkas long ago expressed his opinion that ‘‘ most of these so-called Cladodi are in reality Hybodi” (M. Rev. Dent. Surgery, February, 1874), though he seems to think that the great difference between Cladodus and Hybodus lies in the former having the outer- most denticles larger than the intermediate ones, and consequently admits some of these Coal-measure specimens to the genus Cladodus. Ctenacanthus hybodoides has therefore nothing to do with Cladodus, and as regards the other species, I rather think that, if we knew the creatures to which they belonged, they would turn out to repre- sent several types, possibly very different frum each other. But of this I have now no doubt, namely, that the Cladodontide, whether they had spines or not, or whatever the shape of their spines if they had any, constitute a very different family from the Hybodontidae— while the latter on the other hand were closely allied to the Cestra- ciontide. For if Tristychius be a Hybodont, we have now some clue to the structure of an ancient representative of the family. Tristychius, Agassiz. A specimen of Tristychius, from Eskdale, allied to, if not identical with Agassiz’s T. arcuatus, shows the greater part of the body with the head, one pectoral fin and two dorsal fins. Hach of the dorsal fins has a spine in front. The pectoral shows two large basal pieces which J interpret as mesopterygium and metapterygium, the proptery- gium being either small or fused with the mesopterygium as in 84 Dr. R. H. Traquair—Carboniferous Selachir. Cestracion, while there is no trace of the segmented prolongation of the metapterygium which we saw in the HE. Kilbride Cladodus. This interesting specimen is fatal to Mr. I’. Stock’s idea that the spines in this genus were paired,’ as well as to its location among the Chimeroids as maintained by Prof. Hasse.? That it is a Hybo- dont cannot, in my opinion, be doubted. Orodontide, De Koninck. If the Mesozoic genus Acrodus be a Hybodont,—and its spines are generically indistinguishable from those of Hybodus,—it is difficult to draw any line between the Hybodontidee and Orodontidee. One of the genera which De Koninck and Mr. Davis place in this family must, however go, namely, Lophodus of Romanowski. Romanowski separated from Agassiz’s Helodus such forms as didymus, levissimus, mammillaris, as having one or more prominent elevations on the crown, and a well-developed compressed and_ vertically striated root, while he considered H. planus, which has no such root and no special elevation on its crown, to represent the old genus. Unfortunately both ‘“ Helodus” planus and ‘“ Lophodus” didymus belong to the mouth of the same fish, and that fish is Psephodus magnus! Moreover, as I have once remarked, if the old genus Helodus was to be divided, surely the characters of the type-species, H. simplex of the Coal-measures, ought first to be ascertained and duly considered. Now a fine series of specimens of Helodus simplex, Ag., in the collection of Mr. John Ward, F.G.S., Longton, clearly shows that the teeth in this species have the form of “ Lophodus,” that the entire dentition consisted of teeth generally similar in shape, and that the dorsal fins were armed with spines resembling those of Pleurodus. Whatever be the nature of the teeth which Mr. J. W. Davis retains in, and adds to Helodus, there can be no doubt that H. simplex must remain the type of Agassiz’s genus, in which also Chomatodus cinctus, Ag., ought to be placed, as already indicated both by McCoy and Davis. Cochliodontide. The closeness of the alliance between the Cochliodontide and Orodontidz is shown by the fact that the anterior teeth of Psephodus and Cochliodus are generically indistinguishable from those of Helodus. As seen in Psephodus, which is one of the least specialized of the Cochliodontidz, the posterior teeth lose their deep roots, become flattened, and tend to fuse together into broad inrolled plates. I have a specimen of the broad tooth plate of Psephodus magnus, Ag., which by a groove is divided longitudinally into two portions, which pretty closely represent not uncommon forms of Helodus planus. The grooves on Peecilodus, Deltodus, etc., also to my mind represent the morphological origin of those plates from the fusion of smaller 1 Ann. and Mag. Nat. Hist. (5), xii. 1883, p. 188. * Natiirliches System der Elasmobranchier. Dr. R. H. Traquair—Carboniferous Selachii. 85 and narrower separate teeth. Pleurodus is a well-known form, in which each plate is evidently due to the union, back to front, of a row of helodont teeth whose lateral extremities still tend to project free on each side. That the Cochliodonts all possessed dorsal spines seems highly probable. Those of Pleurodus have been described by Hancock and Atthey. Petalodontide. If we take Ctenoptychius apicalis, Ag., as the type of its genus, I must own that I fail to see any valid reason for separating Ctenopetalus from it, and even Petalodus is scarcely entitled to distinction. Harpacodus differs in having only one fold or plait at the junction of the crown and root, and it is in this genus that Mr. J. W. Davis proposes to include Ctenoptychius pectinatus of Agassiz. But Cteno- ptychius pectinatus is not provided with any “fold” of enamel below the crown comparable to those in Ct. apicalis, or to the single one in Harpacodus, while its root differs very considerably in shape, being divided below into a number of small rootlets, somewhat after the manner of Polyrhizodus. A new genus is therefore necessary for it, for which I propose the name Callopristodus. Oracanthus. Some time ago Mr. R. Craig, of Langsyde, Beith, lent me a small spine from the shale above the 9-inch coal at Broadstone, Ayrshire (Carboniferous Limestone series), which is apparently undescribed. It is small, flattened and broadly triangular, the anterior margin being 1 inch in length, the posterior 12, the base } inch in breadth. The apex ends in a sharp spike, and just below this on the posterior margin are two others directed backwards. Externally the surface is ornamented with distinct furrows running parallel to the anterior and posterior margins, consequently tending to radiate from the apex towards the base, and giving the surface a feebly ribbed appearance. On these ribs are small tubercles, irregularly placed towards the apex, then becoming arranged in lines which proceed obliquely, or with a slight sigmoid curvature, across the surface from behind down- wards and forwards. I have seen other specimens of the same spine from the Carboniferous Limestone “ Bone-bed ” at Abden, Fifeshire, collected by Messrs. W. Anderson and W. Tait Kinnear, which show that the walls were thin and the spine consequently extremely hollow. In these specimens the external ribbing is also feeble, and the tubercles more thickly placed. In their general configuration and in the nature of their surface ornament, the resemblance of this spine to Oracanthus is obvious, although the posterior area is not so sharply defined, and though neither of the sides is notched or sinuated on the lower margin as is, so far as my observation goes, usually the case in the genus mentioned. It has, perhaps, still thinner walls than in the typical Oracanthi, and might on that account be referred to St. John and Worthen’s genus Pnigeacanthus ; but the generic distinction of this from Oracanthus is doubtful. No Oracanthus has hitherto been described with spikelets 86 Dr. Rk. H. Traquair— Carboniferous Selachit. at the apex, but as the apices are more or less worn, a ready explana- tion of their absence is obtained. I therefore designate this spine Oracanthus armigerus, with the remark that if it be not a true Oracanthus, it is an excessively closely allied form. Mr. Davis recognizes that the spines of Oracanthus existed in pairs, and are not bilaterally symmetrical, having one side larger than the other; but when he refers them to the “ posterior termination ” of the body, hints at removing the genus to the “ Placodermic Ganoids,” and figures a whole series of really undeterminable fragments as bones of the head of this supposed Placoderm, we can hardly follow him. I have carefully gone over all the specimens in the British Museum which he has figured as “‘ upper jaw,” “central bone of cranium,” ete., and can find no evidence for such determinations. I have also examined microscopic sections of Oracanthus, and find that they consist of Selachian dentine. And we may also appeal to the obvious resemblance, which the spines of Oracanthus bear to the thin-walled triangular appendages often found associated with Gyracauthus. which, though not “ carpal bones,” as Messrs. Hancock and Atthey imagined, are unquestionably Selachian in their nature. The writer of a review of Mr. Davis’s work, which appeared in the GrotoctcaL MaGazine for November, 1883, does not believe that the Oracanthi formed the posterior extremity of the body of a Placodermic Ganoid, but that “it seems probable that they may have occupied a lateral position on the head of these old Elasmobranch fishes.” And if I am right in my determination of Oracanthus armigerus, sufficient corroboration of this view has now turned up. In the Museum of Science and Art, Edinburgh, there is a specimen from the Eskdale beds, showing the head of a small Selachian, crushed vertically, along with part of the body, the latter being, however, bady preserved. In the head are broken remains of several large flattened-convex tooth-plates, extremely Cochliodont in aspect, but too imperfect for identification with any known genus or species. But the great point of interest is that each postero- lateral angle of the head projects in a pointed process like the corner of a Cephalaspis buckler, and that process is—the spine lanes I have described as Oracanthus armigerus. I think there can be no further doubt that the position of the Oracanthus spines is on the head of a Selachian, and not on the tail of a Placodermic Ganoid. Addendum to Cladodontide. I have long been of opinion that the teeth from Borough Lee, which I described as Cladodus bicuspidatus, and which never show more than two cones, a large one and one small lateral one, which is absent in some specimens, ought to be included in a new genus distinct from Cladodus. I therefore propose for this form the name Dicentrodus, and venture to express an opinion that it will turn out to be more allied to Diplodus than to Cladodus. Notices of Memoirs—W. P. Jervis—On Earthquakes. 87 NOTICES OF MEMOTRS. ————.$\—— W. P. Jervis on EartaqQuakes. L CAY. W. P. JERVIS, F.G.S., Keeper of the Royal Industrial Museum of Italy, has published his Lecture to the Philotechnic Society, Turin, on the nature and causes of Earthquakes, with especial reference to that of February last at and near Mentone. This is a careful study of the earthquake of 1887 in North-western Italy and the neighbouring parts of France and Switzerland, estab- lishing certain facts and advancing some possibly new hypotheses. An earthquake-area being regarded as that in which the shocks have sufficient force to be sensible to man, this earthquake had no con- nection with any volcanic action, and the movements were not propagated to the volcanic region of Central and Southern Italy. An outward external area, including the parts where the seismic disturb- ance was manifested by very delicate instruments and magnetized bars, would, however, bring us nearer to the region of extinct volcanoes in Central Italy. After a close examination of the disturbance of springs and fountains, caused by the sliding or derangement of strata close to the surface, the result arrived at was that Mont Mercantour in the Maritime Alps, west of the Col di Tenda, was the centre of seismic action. That mountain and others associated with it seem to have been the foci of an elliptical, but nearly circular, area of shocks, with its greater axis of about 485 kilometres. The length of the axes of the outer area of shocks perceptible only by seismic or other instruments cannot be determined, the movements depending on the nature of the rocks; probably they were twice the length of the other axes. The summit of the Maritime Alps, from a short distance N.W. of the Mercantour to the junction of the Alps and Apennines above Savona, seems to have divided the earthquake-area. That part towards the Mediterranean and the bed of the sea itself were subject as well to vorticose as to undulatory and subsultory shocks. The lateral boundaries were defined by slight fissures (from one to two or three millimetres wide) in the rocks or soil, in a direction perpendicular to the Maritime Alps, from near the Mercantour to the vicinity of Mentone, and from the mountains to near Savona. The vorticose action was most curious, especially near Mentone, where crosses and upper stones or statuettes of marble were turned round 30° or 45° in the Protestant cemetery. Elsewhere only undulatory and subsultory shocks were apparent. A table of places affected, duration of shocks, and geological nature of the ground is given. Some of the physiological effects before and during the earthquake are noticed, also the hearing of strange sounds in the stillness of the night, as if at a great depth underground. The slow changes of level along the coast from Marseilles to 88 Notices of Memoirs—W. P. Jervis—On Earthquakes. Genoa,—the sinking of Roman buildings below the sea-level at the coast-line near the former mouth of the Rhone,—and the fact of stone-boring Molluses being found many metres above the sea-level in other parts—led Issel to say that this coast-line is subject to slow upheavals and depressions; and these Mr. Jervis believes to be due to the district being the area of repeated earthquakes similar to that of last spring. But as the earthquakes seem to be due to the descent or sinking of mountain-masses towards the centre of the globe, it would seem that they could not be repeated without the gradual lowering of the mountains. Mr. Jervis, however, proposes the hypothesis that there is an extra-mundane cause of upheaval of certain mountain-groups. Referring to Flammarion as being probably correct on the whole, though very poetic and too much of a scenic artist to follow details patiently, Mr. Jervis proceeds with the idea that the sun and moon, in certain positions, may be able to attract a given mountain-mass very gradually, and to an exceedingly small extent,—such process being repeated again and again, each time causing a still further elevation of insensible height. In time, unstable equilibrium having been produced (especially at given moments following the transient recurrences of celestial attraction), terrestrial gravitation interferes, and the upheaved masses settle down, in some instances with rupture of the strata. Thus there are two phases of the disturbance ;—first, a gentle and imperceptible upheaval, so gradual as to be unappreciable by our senses, and never yet established, except on a coast-line where the sea-level gives a fixed point of comparison. This might, however, be as fully proved inland, were the heights of fixed objects on mountains (such as the summit of a building, a signal stone, etc.) determined with mathematical precision, instead of the ever-varying mountain-top (as Mont Bianc) being taken, which may be worn down one to twenty feet in a century by frost and rain, and possibly be again upheaved from time to time so as to restore the geographical relief. The earthquake, as it is called, would then be the phenomena caused by the influence of terrestrial gravitation,—the fall by which stable equilibrium is secured. In the author’s opinion the elevatory process by far exceeds that of depression, allowing full play for the ever-active erosion, by which the Alps, for instance, may have been worn down even hundreds of feet in historic times. Are not earth- quakes, then, absolutely necessary for restoring in some parts of the globe the equilibrium of certain forces and agents, as electricity ? Do they not help to maintain the balance between the heights of mountains and the depths of seas ? The defective method of buildings, especially with vaults, allow of much of the disasters in earthquake-areas, and the author points out some practical technical precautions and the building-materials most fit for use in these places. Reviews—Prof. A. Gaudry—Aneestry of our Animals. 89 ae) SER Mig as Ea VV io I—Tue AncEstry oF ouR ANIMALS. Les Ancirres DE Nos ANIMAUX DANS LES Temps Gf&OLOGIQUES. By Aupert Gaupry. 12mo. (Paris, 1888.) N this fascinating little volume of 296 pages, illustrated by a frontispiece and 48 woodcuts, of which several occupy an entire page, and are printed as plates, we are glad to welcome another of Prof. Gaudry’s valuable and interesting contributions to the history of Fossil Mammalia. The first chapter is a brief réswmé of some of the more important steps in the progress of Paleeontology, with a list of names of many famous workers in various branches. In the second we have an interesting discussion on the importance of the degree of evolu- tion of the contained fossil Vertebrates in regard to the determi- nation of the age of strata in different parts of the globe; in which is given a valuable table of the date of appearance of some of the more important groups of Vertebrates. Great weight is here attached by the author to the degree of specialization of the various genera of Selenodont Artiodactylia, as indicative of the relative age of the beds in which they occur: and illustrations of the doctrine of migration and colonization are given from the Mesozoic Mollusca. With the third chapter we enter on the proper subject of the volume—or the evolution of the Tertiary Mammalia; and here we find a large number of excellent illustrations of the chief types of dental and pedal structure, reproduced from the author’s larger work on the same subject. This subject in the two succeeding chapters is further specially illustrated by the history of the fossil Mammals of Pikermi in Attica, and of Mont Lebéron in Vaucluse, which have been rendered classic by the author’s earlier monographs ; and some very interesting suggestions are made as to the influence which the fossil bones of the “former area may have exerted on the mythologies and metamorphoses of the Greek and Roman classic wilters. The last two chapters are devoted more especially to the Palaeon- tology of the Paris Museum; the seventh containing a review of the works of the author’s predecessors i in the chair of Palaontolog gy. Excellent figures are given in the eighth chapter of some of the more important skeletons of Mammals ‘which adorn the Mammalian Gallery, among which we may especially notice Mastodon angustidens, Glyptodon typus, Palgotherium magnum, and Scelidotherium lepto- cephalum. We may conclude our brief notice of this volume, which we can heartily commend to all our readers —whether they be paleeontolo- gists or not—by some extracts from the end of the sixth chapter which are well worth the attention of those who are flooding our literature with the names of legions of so-called new species and genera. ._M. Gaudry observes, “ We must acknowledge that although the old 90 Reviews—K. Pettersen’s Geology of North of Norway. system of making a special name for the slightest variation is conveni- ent, yet in distinguishing varieties from species paleontologists are exposed to many errors. In the living world, when the descendants from a single type present differences, which do not prevent the pro- duction of fertile offspring with the parent form, they are considered merely as varieties of the same species; but when these differences are such as to prevent the production of fertile offspring, they are regarded as indicating a different species. In paleeontology not only are we unable to avail ourselves of this criterion, but it is difficult to guide ourselves by the analogies offered by existing animals, since there is an extreme inequality in the external characters separating varieties and species; as, for example, the varieties of the Dog differ more from one another than does the Ass from the Horse. “This shows that we can only approximate among fossil forms to the degree of difference indicating a variety or a species. But, in order to come as near as possible to the truth, we should adopt the following plan :—viz. that when the differences separating fossil animals are of no importance from an evolutionary point of view, we may be permitted to regard such animals as mere varieties of a single species; that is to say, that they were all probably capable of producing fertile offspring among themselves.” Numerous examples are then cited of differences which may be regarded respectively as varietal and specific; the different propor- tions of the limb-bones of the Pikermi Hipparions being given as an instance of the former, while the three digits of the European H. gracile as contrasted with the single one of the Indian H. sivalensis are instanced as good specific characters. In conclusion it is observed, ‘That whatever may be the difficulty in marking the distinction between fossil species and varieties, I consider this distinction as worthy the attention of naturalists. The history of past forms reveals, indeed, a succession of unde- finable differences (nuancés indefiniés), which the Divine Wisdom can codrdinate, but to desire to mark each of which by a special name is to only prepare lists without end, in which human weak- ness must lose itself!” We cordially agree with these concluding remarks, and have no doubt that the author would extend them to embrace genera and the larger groups. The time has, indeed, come when we ought to accentuate the resemblances rather than the differences which we find among allied fossil forms; and to recognize that both in the case of specific and generic names it is advisable to use them in a much wider and less defined sense than we are accustomed to do when our study is restricted to the comparatively small fauna of the present day. Re: II.—DrEN NorD-NoRSKE rFJELDByGNING. , AF Karu PETTERSEN. Separataftryk af Tromsoe Museums Arshefter X. ‘Tromsoe, 1887. 8vo. pp. 174, taf. i—iii. HE author has’ been engaged since 1865 in working out the geological structure of the mountain district of North Norway, Reports and Procecdings—Geological Society of London. 91 and he now proposes to give in a connected form the results of his researches. This first part treats more particwarly of the oldest series of the Archean rocks, which is developed throughout the island bordering the coast, from Lofoten to the North Cape, and on the deeply indented coast-line of the mainland, and again makes its appearance in the interior of the country near the border-line between Norway and Finnish and Swedish Lapland. The rocks of the littoral or western series are named by the author gneiss-granite, whilst those of the Eastern are termed the inland granite. Between these series, which have a generally south-west to north-east direc- tion, there is a belt of newer crystalline schists about 100 kilométres (62 miles) in width, which the author believes to be deposited in a basin-shaped depression of the older rocks. The gneiss-granite series consists of beds of gneiss intermingled with granite, but the granite presents no evidence of having been subsequently intruded into the gniess; it is of the same character as the gneiss, and there is a gradual transition from the one into the other. There are also frequent beds of pure quartz interdeposited iu the gneiss-granite series. The author believes that all these rocks are of sedimentary origin, and that the materials of the gneiss have been derived from older granitoid rocks, which could not have been situated in the Scandinavian Peninsula or to the east of it, but probably existed in the area now occupied by the North Atlantic Ocean. From this supposed ancient continent the author believes that the Laurentian gneiss of North America was also derived, as well as those newer crystalline schists which fill up the basin formed by the gneiss-granite series in the Scandinavian Peninsula. These schists reach a thickness of 1000 métres, they are quite unfossiliferous, but they are believed to belong to the Cambrian or lowest Silurian epoch. The author gives an orographical review of the region and detailed descriptions of the geological structure of the different islands, as well as vertical sections in the accompanying plates. G. J. H. I=v JS OrixaesS) PNINfD) ASsssOe pats aD wees ———>—_ GroLocicaL Society oF Lonpon. I.—December 21, 1887.—Prof. J. W. Judd, F.R.S., President, in the Chair. The President announced that the Fourth Meeting of the Inter- national Geological Congress will be held in London in September next on the 17th and following days. An Organizing Committee has nominated the following Officers :—Honorary President, Prof. 'T. H. Huxley, D.C.L., LL.D., F.R.S. President, Prof. J. Prestwich, M.A., F.RS. Vice-Presidents, the President of the Geological Society, the Director-General of the Geological Survey, and Prof. T. M*Kenny Hughes, M.A. Treasurer, F. W. Rudler. General Secretaries, J. W. Hulke, F R.S., and W. Topley. Steps are being taken to enlist the cooperation of all persons interested in Geolog 92 Reports and Proceedings— and the allied branches of science. Particulars will be immediately announced by the Committee. Fellows of the Society are invited to jom the Congress and to assist in making the Meeting a success. The following communications were read :— 1. “On the Correlation of some of the Eocene Strata in the Ter- tiary Basins of England, Belgium, and the North of France.” By Prof. Joseph Prestwich, M.A., F.R.S., F.G.S. Although the relations of the several series have been for the most part established, there are still differences of opinion as to the exact relation of the Sable de Bracheux and of the Soissonnais to the English series; of the Oldhaven Beds to the Woolwich series ; and of the London Clay and Lower and Upper Bagshots to equivalent strata in the Paris basin. The author referred to the usual classifi- cation of the Eocene Series, and proceeded to deal with each group in ascending order. The Calcaire de Mons is not represented in England, but may be in France by the Strontianiferous marls of Meudon. It contains a rich molluscan fauna, including 800 species of Gasteropods, many of which are peculiar, but all the genera are Tertiary forms. ‘The Heersian are beds of local occurrence, and the author sees no good reason for separating them from the Lower Landenian or Thanet Sands. We gave reasons for excluding the Sands of Bracheux from this group. Out of 28 Pegwell-bay species, 10 are common to the Lower Landenian, and 5 to the Bracheux Sands, which present a marked analogy with the Woolwich Series. These Sands of Bracheux are replaced in the neighbourhood of Paris by red and mottled clays. Out of 45 species at Beauvais only 6 are common to the Thanet Sands and 10 to the Woolwich Series. Out of 75 species in the Woolwich and Reading Beds 19 occur in the Bracheux Beds, if we add to these latter the Sands of Chalons-sur-Vesles. Respecting the Basement Bed of the London Clay (Oldhaven Beds in part), the author would exclude the Sundridge and Charlton fossils, which should be placed on a level with the Upper Marine Beds of Woolwich. He allowed that the former were deposited on an eroded surface, but this involves no real unconformity, whilst the palzeonto- logical evidence is in favour of this view, since out of 57 species in the Sundridge and associated beds, only 16 are common to the London Clay. He therefore objected to the quadruple division. Hither the Oldhaven should go with the Woolwich or with the Basement Bed. He admitted that the term “Basement Bed” is objectionable, and preferred Mr. Whitaker’s term for the series, as he would limit it. The Lower Bagshot Sands.—The author would call ‘“ London Sands,” whose Belgian equivalent is the Upper Ypresian, and the French the Sands of Cuise-la-Motte, forming the uppermost series of the Lower Hocene. A group of fossils has been discovered in the Upper Ypresian sands of Belgium, which leaves no doubt of their being of Lower Kocene age, and consequently the Lower Bagshots must be placed upon the same horizon. There is no separating line of erosion between the London Clay and the Lower Bagshots, the Geological Society of London. 93 upper part of the former is sandy, and the lower part of the latter frequently argillaceous. Similarly no definite lme can be drawn between the Upper and Lower Ypresian; but in both countries this series is separated from overlying beds by a well-marked line of erosion. So also in France the base of the Calcaire Grossier (Bracklesham Beds) is a pebbly greensand resting on an eroded surface of the Sands of the Cuise-de-la-Motte. In Belgium, in Whitecliff Bay, and in the Bagshot district the Upper Hocene rests upon an eroded surface of the Lower Hocene. Subjoined is the author’s proposed classification of the Kocene :— ( ENGLAND. Brier. France (Paris Basin). : | a. Barton Beds. a. Wemmelian. a, Sables Moyens or Grés 3 J de Beauchamp. = Saree aaa p b. Bracklesham Beds. Lakenian b. Upper Calcaire Grossier | = Upper and and | 6*. Middle Bagshots. Bruxellian. b*. Glauconie Grossiére. ( | Wanting. Paniselian London Sands = Sands of Cuise-la- Motte. Lower Bagshot. Upper Ypresian. London Clay. Lower Ypresian. Wanting. ; Basement or Oldhaven Sables Inférieurs of the = Beds. P [ Soissonnais, including =< | Woolwich and Read- U Tiandeni + the Marls and Sands of 3 ing Beds. Dee eerrercut 7: | Rilly, the ‘Lignites’ and Sands of Bracheux. Lower Landenian Sands of St. Omer, Douai, Thanet Sands and Heersian. and La Feére. | Wanting. Calcaire de Mons. Strontianiferous Marl of L Meudon ? 2. “On the Cambrian and Associated Rocks in North-west Caer- narvonshire.” By Prof. J. F. Blake, M.A., F.G.S. After referring to the published views of Professor Sedgwick, Sir A. C. Ramsay, and the Geological Survey, Professors Hughes and Bonney and Dr. Hicks concerning the area in question and especially as to the presence or absence of Precambrian rocks, the author gave an account of his own explorations and their results, the principal of which were the following. In the Bangor and Caernarvon area three distinct conglomerates had been confounded. The only one that showed distinct uncon- formity on the underlying rock was of Arenig (Ordovician) age. The rocks of the southern and central portion of the area were essentially of igneous origin and might be distinguished into two groups, the southern probably intrusive, the northern certainly eruptive. ‘There is no evidence to show what interval of time elapsed between the production of these two groups, nor which of them is the earlier, although the author regards it as more probable that the southern mass is of the earlier date and overlain by the northern portions. ‘The Bangor beds are derived from the denudation of the 94 Reports and Proceedings— voleanic series, and of rocks which may have been associated with it, and they contain a series of conformable conglomerates of which the great conglomerates near Bangor are members. They are the continuation of the Cambrian rocks seen to the east, and have not undergone any serious alteration. The porphyries of Llyn Padarn and Moel Tryfaen are contemporaneous lava-flows in the midst of the Cambrian series, the overlying conglomerates being derived from them and from the sedimentary Cambrian rocks to the west; and hence there is no certain proof of there being any Precambrian rocks in the whole district, though it is probable that the rock near Caernarvon belongs to an epoch distinct from and anterior to the Cambrian. IJ.—January 11, 1888.—Prof. J. W. Judd, F.R.S., President, in the chair.—The following communications were read :— 1. “On the Law that governs the Action of Flowing Streams.” By R. D. Oldham, Esq., F.G.S. The author, after describing how his attention was drawn to the subject, proceeded to an investigation of the law that governs the action of a flowing stream. Having accepted as a fundamental principle that the velocity of a stream will always tend to become such as is just sufficient to transport the solid burden cast on to the stream, and pointed out that the principle is almost axiomatic in its nature, he finds that, where untrammelled by exterior conditions, a stream will be alternately confined to a single, well-defined, deep channel, and spread out into a number of ill-defined, shallow channels, the former being defined as a “reach,” the latter as a ‘“‘fan,” that the gradient in the “reach” is less than in the “ fan,” and that both “reach” and “fan” will continually be encroaching at their upper ends, and being encroached upon at their lower ends. After detailing some general considerations which show that what should occur according to hypothesis does actually occur in nature, he indicated that the accurate and detailed levels taken in connexion with the Ganges Canal do actually show this alternation of “reach” and “fan,” that the gradients are higher in the latter, as they should be, and that the records of the Canal show the retro- gression of ‘“ fan” and “reach” demanded by the hypothesis. Accepting this agreement of fact with hypothesis as proof of the correctness of the latter, it follows that the fundamental principle on which it is founded is correct, and that, in the absence of inter- fering causes of greater potency, it is the coarseness or fineness of the débris cast upon-a stream that will determine its gradient and velocity, and not, as stated in text-books, the velocity of a stream that will determine its gradient and the coarseness of the débris transported by it:—a conclusion that might be arrived at inde- pendently, from the fact that it is in the upper reaches of a stream, where coarse débris prevails, that high velocities of current prevail, while in the lower reaches, where the débris is finer in grain, the velocity of current is also diminished. 2. ‘Supplementary Notes on the Stratigraphy of the Bagshot Geological Society of London. 95 Beds of the London Basin.” By the Rev. A. Irving, B.Sc., B.A., F.G.S. This paper contained the results of field-work during the year 1887. Additional notes on the stratigraphy of the Bracknell and Ascot Hills were given, justifying the reading of the country as shown in figs. 1 and 2 of the author’s last paper (Q.J.G.S. August, 1887), the examination of this line of country having been extended as far as Englefield Green. Sections of the beds of the Middle Group as they crop out at Cesar’s Camp, Swinley Park, Ascot, and Sunning- dale, were described and correlated with the 76 feet of beds which . constitute that group in the Well-sections at Wellington College. The stratigraphy of the hills known as Finchampstead Ridges has been worked out from numerous sections on their flanks; and the strata of the Bearwood Hills were correlated directly with them. All along the northern margin a general attenuation of (a) the Lower (fluviatile) Sands, and of (b) the Middle (green earthy) Sands was shown to occur, and in some places on the northern margin they are found to have entirely thinned away, admitting of distinct overlap at more than one horizon. The second part of the paper dealt with the Highclere district, where the author believes he has established the full succession of the three stages of the Bagshot formation, a section being given across the valley south of Highclere Station, showing the succession of the whole Eocene series (with the Ostrea bellovacina-bed for its base) as it is developed there. Some important conclusions were drawn as to the Tertiary physio- graphy of the South of England; and the revised tabulation of the Tertiaries put forward by Prof. Prestwich at the Society’s last meeting was referred to as supporting some of the main points for which the author has contended. 3. “The Red-Rock Series of the Devon Coast Section.” By the Rev. A. Irving, B.Sc., B.A., F.G.S8. From a recent examination of this section, and from the facts furnished by Mr. Ussher’s paper (Q.J.G.S. vol. xxxii. pp. 367 et seq.), the author has arrived at the conclusion that the series of red rocks between the Lias to the east of Seaton and the Carboniferous of Devon, formerly described under the title of ‘‘ New Red Sand- stone,” cover the period of geologic time which that term signified, and that the lower members of the series belong, not to the Trias, but to the Permian or Post-Carboniferous. He considered that at the base of the Budleigh-Salterton pebble- bed there isa physical break of as much significance as that between the Trias and the Permian of the Midlands. From this point east- wards the Triassic system is represented by a series of rocks quite comparable with the Bunter and Keuper of the Midlands, the Bunter being here represented by the Middle Division (about 200 feet thick) and the Upper Division of Prof. Hull. These pass under the basement sandstone-series of the Keuper below High Peak and Peak Hills, are brought up again by faulting at Sidmouth, and dip beneath the Keuper again east of the Sid, 96 Correspondence—Mr. W. D. Carr. from which point eastwards the whole Keuper Division is exposed, with quite a normal facies, as seen in the Midlands, in Central Germany (Thiiringen, Jena), and in the Neckar Valley. In the marls which underlie the Budleigh-Salterton Pebble-bed, he recognized the equivalents of the Permian Marls of Warwick- shire and Nottinghamshire, and of the Zechstein Marls of. Germany. These pass, by a gradual transition, through Sandstones, becoming more and more brecciated, into the great brecciated series of Dawlish and Teignmouth, which were regarded as the equivalents of the great Permian breccias of the west of England, of Ireland, and of the Lower Rothliegendes of Germany. All the rocks below the Budleigh-Salterton Pebble-bed were regarded as the assorted materials furnished by the detritus of the Paleozoic mountain-region of Devon, Cornwall, and Brittany, and as representing the waste and degradation of that region, deposited on the mountain-flanks and in land-locked bays during Post-Carboni- ferous times, the marls being compared with the Nyirok of the Austrian geologists. CORRS @aAN eae asiS aaa ERRATIC BOULDERS. Srr,—Your notice of Prof. Hull’s paper on “ Boulder Stones,” read before the British Association last year, recalls my attention to an interesting example of a boulder I came across during a geological excursion in the Grantham district (Sheet 75) some four or five years ago, which I believe exceeds the dimensions of the largest given by Prof. Hull. I had stayed the night at the village of Marston, about five or six miles west of Ancaster, and was making my way in the early morning towards the quarries of our noted Lincolnshire freestone, situate at the latter village, when I noticed a rough accom- modation road metalled with Lincolnshire Oolite. This struck me as rather strange, there being several quarries in the Marlstone much nearer at hand. I followed it up, and ultimately found the quarry from which the stone was obtained, a quarry in Lilncolnshire Oolite! at least five miles further west than one would expect to find such a thing. The quarry, on examination, proved to be excavated in a huge boulder stranded on a hill of Middle Lias clay capped by Marl- stone. The boulder was almost covered by a very tough chocolate- coloured Boulder-clay, containing Lias fossils, and grassed over. A roadway was cut into it for a distance of twelve or fifteen yards (writing from memory). ‘The definite outline of boulder was obscured in all directions except the entrance to the quarry, where the workmen had cut down to the Lias below, the lines of bedding dipped about 20 per cent. N.W. This stone had probably travelled from the neighbourhood of Ancaster, five miles east, where the line of cliff (escarpment of the Oolites) is cut back and forms a sort of gorge; this is the nearest point it could possibly have come from. W. D. Carr. oO Decad 1. Mag.188 Geo West,Newman &Co.1mp. EC Knight ith. Seandinavian Phylloearida. THE GEOLOGICAL MAGAZINE. NEW) "SERIES: DECADE lly VQEI IN. No. III.—MARCH, 1888. (@Qizal Ee weIN( Min) PIS ya be KOA mnt lS) =e T.—On Some ScanDINAvVIAN PHyYLLocariDA. By Prof. T. Rupert Jonzs, F.R.S., and Dr. Henry Woopwarp, F.R.S. (PLATE V.) OME Phyllocarida from the Silurian strata of Scandinavia (Sweden and the Island of Gothland) are represented by speci- mens in the State Museum at Stockholm. Drawings, casts, or the specimens themselves have been shown to us by our friend Professor Gustav Lindstrém, F.C.G.S., and we have arrived at the following conclusions as to their jrelationships.—See the ‘“ Fifth Report on the Fossil Phyllopoda of the Paleozoic Rocks,” read at the Manchester Meeting of the British Association for the Advancement of Science, September 3, 1887 (printed and issued at the same date), pp. 1-3. I, CERATIOCARIS. Monograph of the British Palsozoic Phyllocarida, Pal. Soc., by T. R. J. & H. W., 1888, pp. 9-13. 1. Crrariocaris Aneenini, T.R.J.& H.W. Plate V. Fig. 1. Fifth Report, etc., 1887, p. 1. This unique specimen is a long, stout, trifid caudal appendage, consisting of the style or telson (145 mm. long, and 17 mm. broad at the top) and two stylets (each 75 mm. long) lying close together. One of the latter and the style have been broken across by a crush, and the style is not quite perfect at the tip (possibly 15 mm. longer originally). The lower (ventral) surface only is shown. The articulation of the stylets with and beneath the shoulders of the style—that is, under the backward extension or overhanging hinder edge of its head or proximal end—is very distinct. The upper edge of this part of the style (the surface articulating with the ultimate segment) has an undulated profile, with two small, projecting, un- symmetrical, curved, horn-like processes. The style on this its lower aspect has a deep groove along the middle of its upper moiety (obscured at the top), becoming narrow lower down. A slight groove on each side is also present. No delicate ridging is seen, nor any pits for bases of prickles. The stylets are smooth, and apparently subtriangular in section, each bearing one strong ridge on the upper part of the under face (as exposed), DECADE III.—VOL. V.—NO. III. 7 98 Prof. T. R. Jones and Dr. H. Woodward— In these features this form differs from OC. Bohemica,' Barrande, the telson of which is not deeply furrowed on its ventral (under) face; and the latter species has longer stylets, oval in section, and neatly ridged throughout. The Scandinavian specimen occurs, as an impression, in hard black shale (‘Brachiopod-Skiffer’) from the Lower Silurian (Upper Caradoc) of Westergétland (Westrogothia), a province in the western part of the mainland of Sweden. It has been badly figured in Angelin’s unpublished ‘Tab. LIII.’ figs. 18 and 19. Fig. 1 is taken from a plaster cast. 2. Ceratiocaris Bouemica, Barrande. Plate V. Figs. 2—6, 10. 1853. Ceratiocaris (Leptocheles) Bohemicus, Barr. ‘‘ Neues Jahrb. fiir Min.” ete. 1853, Heft. iii. p. 342. 1868. Ceratiocaris Bohemicus, Barr., in Bigsby’s ‘‘ Thesaur. Silur.”’ p. 199. 1872. C. Bohemicus, Barr. ‘Syst. Sil, Bohéme,”’ vol. i. Suppl. p. 447, pl. 19, figs. 1-13. 1885. CO. Bohemica, T.R.J.& H.W. «Third Report on the Paleozoic Phyllopoda,” p. 31 (p. 356, Brit. Assoc. Report for 1885) ; and Fifth Report, etc., 1887, ae In this species the ultimate segment, 50 mm. long, has a linear longitudinal ornament of interrupted raised lines. ‘The telson more than 112 mm. (44 inches) in length, is ridged and furrowed, and has pits (marking the bases of former spines and prickles) along the two outer slopes of its dorsal surface. The lower face has a broad median furrow and two lateral hollow slopes. The head of the telson has a linear ornament like that of the ultimate segment. The stylets are ridged and furrowed, and are somewhat oval in section. Four specimens (Figs. 2, 4, 5, 6), from the cream-coloured lime- stone (Wenlock Shale) of Eksta, Gothland, are portions of the shafts of straight, strong styles (telsons), similar to that of C. Bohemica, and chiefly from the middle and lower parts of the styles. In section these Scandinavian specimens are more equally quadrate than in Barrande’s figs. 7 and 9, pl. 19, “Syst. Sil. Bohéme,” vol. i. Suppl., and the fluting on the lower face is somewhat different. One piece, Fig. 4, is the same as “fig. 5” of Angelin’s unpublished plate “Table B.” Another piece of telson (Fig. 3) of the same kind as the above, shown by a drawing from Stockholm, is from the Sandstone of Bursvik, South Gothland (Wenlock Shale). A small fragment (Fig. 10) from:Lau, Gothland, in cream-coloured fossiliferous limestone (Wenlock), is probably part of a stylet of C. Bohemica, comparable with, but much smaller than, figs. 4, 5, of Barrande’s pl. 19. It tapers rather rapidly, bears several thin ridges on both faces, and is oval in section. 2**, CERATIOCARIS VALIDA (?), J. & W. Plate V. Fig. 7. Monogr. Foss. Phyll. 1888, p. 20. This is a fragment of strong thick telson in cream-coloured lime- stones, differing from C. Bohemica: (1) in being curved (the 1 Syst. Sil. Bohéme, vol. i. Supplement, p. 447, pl. 19, figs. 1-13. Scandinavian Phyllocarida. 99 convexity is dorsal, that is, on the upper surface), (2) in having the two pitted slopes lower down on the sides, and (38) in the section being less quadrate than in C. Bohemica proper. In many respects it approaches C. valida, J. & W. In whitish limestone with Stro- phomena, Trilobites, Tentaculites, Encrinites, ete. (Wenlock Lime- stone), from Rohne, Gothland. 3. Ceratiocaris, sp. Pl. V. Fig. 9. 1887. Ceratiocaris, sp. nov.? T.R. J. & H. W. Fifth Report, etc. p. 2. A fragment of a style or of a stylet. It is somewhat like the last (Fig. 10), but the ridges are fewer, broader, and rounded. This is a drawing sent from Stockholm. The specimen (Mus. Geol. Survey Sweden”) was from Frojel, Gothland (Wenlock Shale). The “ fig. 6” in “ Angelin’s” unpublished “Tab. B” is somewhat like this, but shows six, instead of four rounded ridges. 4, Ceratiocaris concinna, T. R. J. & H. W. Plate V. Fig. 8. 1887. Ceratiocaris concinna, sp. nov. Fifth Report, etc. p. 2. A small portion of a straight, rapidly tapering style, convex on the upper, and concave along the lower face. ‘The section is half- moon-shaped in the upper, and more oblong in the lower part. Two rows of small pits on narrow ridges along the back, one on each side of the raised middle. The test is of a dull, light chestnut tint; it is hollow and filled with limestone. From Fréjel, Gothland. This tapering telson (7 mm. broad at the top, and 44 mm. at the end of the fragment 15 mm. long), differs from any we know of, though it approaches that assigned to C. patula, J. & W. Being very neat in aspect, it has been called concinna. 5. Crratiocaris Sconaryt, Barrande. Plate VI.! Fig. 1. 1872. C. Scharyi, Barr. ‘‘Syst. Sil. Bohéme,’’ vol. i. Suppl. p. 454, pl. 32, figs. “Ld. 1876. @. ey F. Reem. ‘‘ Leth. geogn.” Th. I. ‘‘ Leth. pal.’”’ Expl. pl. 19, go. 6. 1885. C. Scharyi, T. R. J. & H. W. _ Third Report, ete. p. 31 (Brit. Assoc. Report for 1885, p. 856): and 1887, Fifth Report, etc., p. 3. Of this species seven segments (75 mm., ultimate segment 23 mm. long) were described by Barrande. Height of the highest (sixth from the end), 20 mm.; height at the end of the ultimate segment, 10 mm. Proximal portion of the trifid appendage, attached in place, is ornamented with a delicate imbrication of raised, leaf-shaped lines, like pointed arches, with a minute tracery of smaller leaf-like pattern within them: all pointing backwards. The same ornament appears on the head or proximal portion of the telson also. The ornament has some resemblance to the pattern on Hurypterus; it occurs also on C. Deweti, Hall, and on some British forms. This species belongs to Barrande’s Stage H e 1 of the Bohemian formations. From Scandinavia we have seen seven abdominal segments (first and last imperfect), some with the test, some shown only by 1 Plate VI. will appear in the April Number Grou. Mag. 100 Prof. Jones & Dr. Woodward —Scandinavian Phyllocarida. impressions ; crushed laterally, and showing the whole half from the. dorsal ridge to the epimeral border. In shape they are not unlike those of C. Scharyi, Barrande. They are ornamented with a strong leaf-like lattice-pattern, as in that species. The apices of some of the triangles thicken and form a kind of elongate drop-like ornament (Pl. VI. Fig. 16). The smaller (secondary) lattice-work inside each leaf-mark is not so distinct as in Barrande’s fig. 27. In hard blue micaceous shale (Ludlow Series), from the lake Ringsjon, Scania. This specimen is a portion of “fig. 1” in Angelin’s unpublished “Tab. B.” That figure shows a ‘large portion of the ultimate segment, and the complete penultimate segment; but the former and a third of the latter have been broken away, and a fracture passes between the two next segments. 6. CERATIOCARIS PECTINATA, T. R. J. & H. W. Plate VI. Fig. 2. 1887. Ceratiocaris pectinata, sp. nov. Fifth Report, etc. p. 3. A portion of an ultimate segment (146 mm.), with a telson (fragment 30 mm.) and one stylet (not quite perfect, 22 mm.). The segment retains scarcely any of the test, but shows traces of an ornament of irregular small tubercles and interrupted longitudinal lines; and the distal margin of the segment has a coarse comb-like fringe, consisting of a regular set of thin elongate tubercles, remind- ing one of the drop-like tubercles on marginal parts of some Eurypterids. The head of the telson is wrinkled longitudinally, and both the style and the stylet are ridged and furrowed. This form being new to us, its comb-like fringe suggested the name pectinata. In earthy micaceous blue-grey limestone, from the Ringsjén, Scania. This specimen is “fig. 2” in Angelin’s unpublished “Tab. B.” EXPLANATION OF PLATE VY. (ALL oF THE FicuREs or THE Naturat Size Excerr Fie. 8 4.) Fie. 1. Ceratiocaris Angelini, J. & W. View of the underside of the style and stylets. From a plaster cast. The style is not quite perfect. 5, 24, b,c. Ceratiocaris Bohemica, Barr. Views of a part of the butt-end of a style. a, side view; 4, dorsal aspect; ¢, section. » 38,44, 6; 5a, b; 6 a, db. The same. Dorsal views and sections of portions of styles. », 14, b. C. valida (?), J. & W. Side view and section of a portion of a style. » 84, 6, ¢. C. concinna, J. & W. Views of a broken style. 8 a, dorsal view; 8 b, a row of pits, enlarged 2 diam.; 8 ¢, sectional area. », 9. Ceratiocaris, sp. noy. ? View of the underside of a stylet. », 10 a, b. C. Bohemica, Barr. View of the underside of a stylet, and its sectional area. 1 Plate VI. will appear in the April Number of the GrotogicaL Macazine.. (Lo be continued in our neat Number.) Dr. Rk. H. Traquair—Carboniferous Selachit. 101 Iil.—Furruer Nores on Carsonirerovus SEeLacuit.! By Dr. R. H. Traevair, F.R.S., F.G.S. Anodontacanthus and Pleuracanthus. die 1881? Mr. J. W. Davis proposed the genus Anodontacanthus for certain straight spines resembling Plewracanthus, but differing in the absence of the two rows of denticles. Three species are included:—A. acutus and obtusus, from the Coal-measures of Yorkshire, and A. fastigiatus, from the Blackband Ironstone of Carboniferous Limestone age at Loanhead, near Edinburgh. Toffer no criticism on the two Yorkshire species, nor have I seen the type of the Midlothian 4. fastigiatus. In the large collection of spines which I have from Loanhead, there are, however, many which I refer without doubt to the last-named species. Now, although some of these are smocth and without denticles, others show, in all stages of apparent wearing away, undoubted stumps of denticles, whereby the species fastigiatus falls into Pleuracanthus, as that genus at present stands. It is to be noted that a large number of the spines found in this Ironstone (Loanhead and Borough Lee, No. 2) are singularly worn or eroded all over, as if they had been long exposed to the action of agencies, chemical or mechanical, tending to destroy the surface. I have seen a spine of Gyracanthus from that bed having every vestige of the surface ornament, so elaborate in that genus, removed, and I had to examine it microscopically before I felt absolutely sure of its genus. Other Gyracanthi, etc., are found in every stage of “ polishing off.” But this phenomenon is by no means peculiar to the spines and other fish remains from Loanhead; it is tolerably frequent elsewhere, and is apt to lead into error those who have not yet learned to take it into account. /Pleuracanthus erectus, Davis (Q.J.G.S. vol. xxxvi. p. 826), is to my mind nothing but an eroded specimen of Pl. levissimus, Ag., the ‘‘ very blunt-pointed ” character of the denticles being thus amply accounted for, and I have a speci- men of Pl. elegans, Traq., from Loanhead, which shows precisely the same condition. Pl. Wardi, Davis (ib. p. 834), probably owes the bluntness of its denticles to the same cause. And | feel pretty well persuaded that T’. Stock’s Lophacanthus Taylori (Ann. and Mag. Nat. Hist. 5th ser. vol. v. p. 217) is nothing but a worn specimen of Pleuracanthus (Orthacanthus) cylindricus, Ag. Pristodus falcatus, Davis (ex Agassiz MS8.). Mr. Davis, in his large work on the Carboniferous Limestone Fishes of Great Britain, in describing a remarkable tooth to which Agassiz had given the MS. name Pristodus falcaitus, makes no reference to the fact that a closely allied species had been already, in 1875, figured and described by Mr. R. Etheridge, jun., in the GuroLocicaL Macazrnz, under the name of Petalorhynchus? Benniei.? Mr. R. Etheridge also mentions that he had been informed by 1 Read before the Royal Physical Society of Edinburgh, February 15th, 1888. 2 Q.J.G.S. vol. xxxvii. p. 427. 3 Gzou. Mac. Dec. II. Vol. II. p. 242, Pl. VIII. Figs. 3 and 4. 102 Dr. R. H. Traquair—Carboniferous Selachir. Mr. W. Davies’ that Mr. W. Horne had exhibited a similar tooth from Wensleydale at the Bradford meeting of the British Associa- tion in 1878, and goes on to say :—‘‘ Mr. Davies is also much im- pressed with its resemblance externally to the uncovered teeth of the Parrot fishes generally, but more especially to the Diodons ; but as the fish which bore this tooth was undoubtedly a Selachian, and the structure of the tooth, within the mouth, so different to that of the Diodons, it can have no affinity with these recent fishes, although very suggestive of a Selachian with a similar form of mouth.” This statement as to affinities by Mr. R. Etheridge, jun., cannot be called in question by any one who has studied the structure of the teeth and jaws of Diodon; nevertheless, six years afterwards, we find Mr. J. W. Davis, at the British Association in 1881, naming this tooth Diodontopsodus, and apparently going back to the idea of its Gymnodont affinities: “In Diodontopsodus the teeth are extremely like those of the existing fish Diodon”’ (Proc. Brit. Assoc. 1881, Trans. Sect. p. 646). And in his large work on the Carboniferous Limestone Fishes he seems still unable to free himself from this idea. At p. 521 he says:—‘“‘In searching for the zoological relationship of Pristodus, a striking and most peculiar resemblance is at once observed between it and some of the Gymno- dont group of the Plectognath group of fishes at present existing. . . - In many respects the fossil teeth from the Mountain Limestone of Yorkshire bear considerable resemblance to those of Diodon. In the general form of the palatal interior, combined with the semi- circular external, trenchant edge of the tooth, the two are almost identical. . . . A comparison of the recent and fossil teeth, however, leads to a natural inference of relationship in some degree, however remote. Hvidence is entirely wanting as to the anatomical structure of Pristodus, and I do not wish to lead to the inference that it was more nearly related than is warranted by the peculiar similarity of the teeth.” I very much fear however that the “peculiar similarity of the teeth” is a very deceptive one after all.” But although Pristodus cannot have had the remotest affinity with Diodon, it is quite an open question as to whether there may not have been some analogy in the form of the jaws, a couple of these peculiar tooth-plates, one above and one below, forming the whole of the armature of the mouth. Rather against this view, however, is the fact that the height of the crown in these teeth is extremely variable, as may be well seen in the extensive series of P. falcatus in the British Museum, and that in some the apex is more acute, or tending to be mucronate, than in others. Mr. J. W. Davis’s Pristicladodus concinnus seems to me to be nothing more or less than a crushed specimen of a species of Pristodus with a more than usually mucronate apex. 1 Formerly of the British Museum. 2 My friend Mr. A. Smith Woodward writes to me that he has, from an examina- tion of specimens from Derbyshire, come to the conclusion that Pristodus Benniei (R. Eth., jun.) is after all distinct specifically from P. faleatus, Ag. Concinnus (Davis) he also is inclined to regard as distinct, and in that case all three names will stand as. species of Pristodus. Dr, R. H. Traquair—Carboniferous Selachit. 1038 Pristicladodus, M‘Coy. There can be no doubt that the specimen from Armagh, in the British Museum, to which Mr. J. W. Davis has given the name of Carcharopsis Colei, is nothing else than a specimen of Pristicladodus dentatus, M‘Coy, with the base broken off. Chondrenchelys problematica, n. gen. & sp. Among the fishes from the Eskdale beds, obtained from Mr. Damon for the Edinburgh Museum, is one whose nature is still more problematical than that of Tarrasius, which it somewhat resembles in external shape. Two specimens in the Hdinburgh Museum have the head and the tail preserved up to near the termina- tion of the latter, and of these the lengths are, respectively, 43 and 7 inches. The shape of the body is singularly elongated and eel- like, the head being small, less than 4 of the total length, while a long, low, continuous dorsal fin runs along the back from not far behind the head to the end of the slender pointed tail. In the larger of these two specimens no structure can be made out in the head at all, owing to the obstinacy with which a layer of matrix adheres to the surface. The smaller affords not much more light as to this part, though the shape of the head appears pointed, and there is some appearance of what is either a mandible or a palato-quadrate arch. It is even difficult to make out whether the substance exhibited be true bone, or calcified cartilage, though there is a spicular-looking body lying longitudinally in the middle of the head, which from its smooth, almost glistening, aspect reminds us of bone. About + inch behind the head, and apparently not at all attached to it, is an evident shoulder-girdle, or coraco-scapular arch, whose direction is obliquely downwards and forwards. Careful examination reveals no composi- tion out of distinct membrane-bones ; on the other hand, its substance has an unmistakeably granular aspect suggestive of calcified cartilage. No trace of paired fins, pectoral or ventral, is visible. Commencing at the head, and passing back under the aforesaid shoulder-girdle to the extremity of the tail is a well-marked vertebral column. Here the axis consists of undoubted centra, which are rather higher than long. They are crushed and flattened laterally, but on careful examination of a most instructive fragment in the collec- tion of the Geological Survey of Scotland, they can clearly be made out to have had the configuration of thin-walled hollow rings, through which a scarcely constricted notochord must have passed. Appended to the dorsal aspect of this chain of centra is a series of bodies representing the neural arches and spines. Lach of these is short, slender, and rod-like, bifurcating below and pointed above, and there seems to be one for each centrum. They are not composed of ordinary bone, but of small granules placed end to end like a string of beads, and that they had not the rigidity of bone is seen from the flexuosities which they often present in their contour. Commencing almost immediately behind the shoulder-girdle, and appended to the neural spines above, is a second series of rod-like bodies represent- 104 _ Prof. H. A. Nicholson—On the Favositide. ing fin-rays or radials, of which there are three or four to each neural spine; they are more slender than the latter, but have the same granular structure. They gradually increase in length towards the posterior third of the body, whence they again fall away towards ‘the end of the tail. The abdominal region extends for 13 inch behind the head: no ribs are visible, the termination of the abdomen being marked by the commencement of a series of hamal elements quite similar in configuration and structure to the neural ones above, and these now extend to the extremity of the tail. No fin-rays are seen on the ventral aspect of the skeleton, nor have I seen any trace of any dermal hard parts. This is indeed one of the strangest fishes as yet yielded by these Eskdale deposits, which have proved so rich in paleichthyological treasures. We are not aware of any ganoid, recent or fossil, whose body is entirely destitute of dermal hard parts, for even the all but naked Polyodon of the present day and also the Carboniferous Phanerosteon have still a few scales on some part of their surface. It seems also scarcely probable, that the apparent absence of mem- brane bones from the head and shoulder-girdle is entirely due to deficient preservation, and the granular structure of the vertebral apophyses and radials is not paralleled so far as I know in any Ganoid. It certainly is not an ordinary Ganoid, nor is it an Acan- thodian. On the other hand, its affinity to the Selachii seems to be indicated by the position of the shoulder-girdle, and by the granular calcification of the vertebral apophyses and radials, and probably also of the head and shoulder-girdle. If it be a Selachian, it is certainly one of a very primitive and at the same time aberrant type. In its long dorsal fin, it resembles Xenacanthus, but there is no cephalic spine, apparently no paired fins (though this may indeed be due to defective preservation), the vertebral centra are more developed, and the two rows of dorsal interspinous cartilages or “« Flossentriiger ” described by Kner in that genus seem to be absent. It is certainly a new, as well as a most interesting form, for which I accordingly propose the name of Chondrenchelys problematica. I1I.—On tur Derecrion or Murat Pores iy THIn SECTIONS OF THE FavosiTipm. By H. Atteyne Nicuouson, M.D., D.Se., F.G.S., Regius Professor of Natural History in the University of Aberdeen. Sa text for the following brief remarks on the recognition of mural pores in thin sections of the Favositoid Corals, I may quote a note appended by Mr. James Thomson, F.G.S., to a recent paper on the genus Lithostrotion (Trans. Edin. Geol. Soc. vol. v. part i. p. 881). The note in question is subjoined, the quotation being verbatim, and, I may add, literatim also :-— “We may, however, attach an undue importance to microscopic examinations. Need I refer to the point raised recently by that erratic and energetic worker, Prof. Alleyne Nicholson, regarding mural pores in the genus Alveolites, the type of which is also in Dr. Prof. H. A. Nicholson—On the Favositide. 105 Fleming’s collection. If he had detected mural pores in microscopic sections, we would have regarded such as being one of the greatest discoveries of modern times. Is it to be expected that such delicate pores could retain their normal aspect, surrounded and impregnated by induced calcareous matter during fossilisation? Indeed, we have failed in detecting the mural pores in the genus Michelinia by the microscope, which is of gigantic proportions in comparison to any of the four species of Alveolites. In, however, weathered specimens of either we find no difficulty in detecting the mural pores, and in no locality have we procured better examples showing such than is to be found in the examples of A. depressa, found in Charleston Quarry, Fifeshire. A variety of Alveolites, which we believe has been rashly relegated to the genus Cheates hyperbolus,' by Nicholson and Htheridge, jun.” So far as concerns the genus Alveolites, Lam., in particular, it is unnecessary to criticise the statements contained in the above note ; since the note itself contains the plainest proof that Mr. Thomson does not know what the genus Alveolites, Lam., is, and that he is not acquainted with any species of the same. The first point is sufficiently shown by his assertion that “the type” of the genus is “in Dr. Fleming’s collection”; whereas the type of the genus Alveolites, as every paleontologist knows, is the familiar A. suborbicularis, Lam., of the Devonian rocks, and is preserved at Paris. ‘The second point is equally clear from his speaking of “ the four species of Alveolites,” as if there were only four species in the genus; the truth being that “the four species” to which he refers (viz. Chatetes septosus, Flem., C. depressa, Flem., C. capillaris, Phill., and C. Htheridgii, Thoms.) belong to the genus Chetetes, Fischer, and are not referable to the genus Alveolites, Lam., at all. As regards the general question involved, in view of all that has been published in recent times as to the minute structure of the Favositoid Corals by Ferd. Roemer, Lindstrom, Schliiter, Frech, Foord, R. Etheridge, jun., the present writer, and others, it is difficult to believe that one who professes to have studied Paleozoic Corals should speak of the recognition of mural pores in thin sections of Alveolites as still unaccomplished,’ or of its possible accomplishment as being “one of the greatest discoveries of modern times.” Even in the days of those great masters—Milne Edwards and Haime—before the method of working by means of thin sections had come into use at all—it was a familiar fact that mural pores could readily be recognized in polished slabs of the Favositoid Corals. Mr. Thomson does not appear to have grasped the elementary fact 1 By ‘‘the genus Oheates hyperbolus’’? Mr. Thomson refers, I presume, to the “‘species”? described by Mr. R. Etheridge, jun., and myself, under the name of Chetetes hyperboreus. 2 Mr. Thomson’s disbelief in the possibility of recognising mural pores in thin sections of the Favositoid Corals is, it may be noted, of comparatively recent growth. Thus, in a paper published in the Proceedings of the Philosophical Society of Glasgow in 1881, Mr. ‘Thomson described and figured what he believed to be mural pores in thin sections of Chetetes Etheridgii, Thoms. sp. A reference to his figure (/oc. cit. pl. i. fig. 7) will show, however, that in this case the supposed ‘‘mural pores’’ are represented in the centre of the calcite filling the visceral chambers of the corallites, and that they are really nothing more than minute granules of calcite. 106 Prof. H. A. Nicholson—On the Favositide. that whatever is shown by a polished vertical or horizontal slice of a Coral will necessarily be shown by corresponding thin sections. A thin section often shows more than a polished slab, but never less. Every one who has ever examined polished specimens of such common Devonian species of Alveolites, as A. suborbicularis, Lam., A. Battersbyi, EK. & H., or A. reticulata, EH. & H., knows that such, as a rule, exhibit the mural pores with the utmost clearness, This being the case, it follows, as a matter of course, that thin sections of such forms show the mural pores, to one who knows what to look for, with at least equal clearness. What is true of the above-mentioned forms is true of the Favositoid Corals generally, in thin sections of which mural pores can usually be detected without any difficulty. This assertion is not at all affected by the fact that in certain states of mineralization any form of the Favositide may fail to yield direct evidence of mural pores, when examined either in polished slabs or in thin sections. The phenomena by which we may recognize in thin sections of the Favositoid Corals the presence of mural pores are, of course, well known to paleontologists generally. For the benefit, however, of those who may be beginning the study of the fossil Corals by means of thin sections, I may briefly indicate the character of these phenomena. In the first place, it is to be remembered what “mural pores” are. In their typical form, mural pores are simply rounded or oval apertures, arranged in longitudinal series, which perforate the walls of adjacent corallites and place adjoining visceral chambers in direct communi- cation. In some cases, the ‘‘mural pore” is not completed; since the thin ‘‘ primordial wall’ which separates adjacent tubes is not actually perforated, but is continuous. In such cases, the cavities of adjacent tubes do not actually communicate, and the so-called ‘‘mural pore” is simply caused by a deficiency, at corresponding ee of the thick layer of secondary sclerenchyma (‘‘stereoplas- a”) which ordinarily coats both sides of the “primordial wall.” fh other cases, again, as in the genus Roemeria and in the typical species of Pachypora, where the above-mentioned layer of secondary sclerenchyma is excessively thick, the ‘‘mural pores” assume the character of longer or shorter tubes which connect adjacent visceral chambers. Whatever may be the precise form assumed by the mural pores, they can usually be readily recognised in thin sections, whether these sections be taken at right angles to the tubes or in a direction corresponding with the long axes of the latter. The facility with which they can be detected depends partly upon the condition of preservation of the specimen examined and partly upon the size and arrangement of the mural pores themselves. With regard to the latter point, the large, often uniserial pores of forms like Alveolites and Pachypora are usually more conspicuous than the generally smaller, often biserial or triserial pores of Favosites and its immediate allies. Bearing the nature of ‘mural pores” in mind, it is easy to recog- nize the phenomena which they present in thin sections. Prof. H. A. Nicholson—On the Favositide. 107 1. Tangential Sections.—Sections taken tangentially to the surface of a Favositoid Coral, so as to cut the corallites at right angles to their length, very commonly exhibit the mural pores. In such cases the mural pore presents itself as a gap in the wall forming the circumference of a corallite (Fig. 1, 4, B, and C, p), the size of this gap depending upon the size of the pore. If the mural pore is not a complete perforation (as sometimes happens), then the gap is crossed by the thin primordial wall of the corallite, the delicate partition thus formed being uncovered on both sides by the layer of Fig. 1. B Fic. 1.—Thin sections of Favositoid Corals, showing the phenomena presented by the mural pores. -A, Tangential section of Favosites sp., from the Devonian of Queensland, enlarged six times. 4’, Vertical section of the same similarly enlarged ; in two of the tubes the section traverses the centre of the visceral chambers, but in one it corresponds in part with the wall of the corallite. B and B’, Tangential and vertical sections of Alveolites Labechei, E. & H., from the Wenlock Limestone of Tronbridge, enlarged ten times. [The septal thorns which characterize this species, as also A. Battersbyi, E. & H., are mostly omitted in the drawing.] Cand C’, Tan- gential and vertical sections of Pachypora sp., trom the Corniferous Limestone of the Falls of the Ohio, enlarged ten times. In all the figures the letter y indicates the mural pores. secondary sclerenchyma which elsewhere lines the wall. In the great majority of well-preserved specimens of species of Favosites, Pachypora, Striatopora, Michelinia, Pleurodictyum, Alveolites, etc., there is usually no difficulty in recognizing the presence of mural pores by the more or less frequent occurrence in tangential sections of the deficiencies in the walls of the corallites above described. In 108 Prof. H. A. Nicholson—On the Favositide. Alveolites itself, the mural pores are generally uniserial, and are placed along the short sides of the compressed corallites ; so that they appear in tangential sections as gaps at the ends of the crescentic tubes (Fig. 1, B). It is hardly necessary to add that a tangential section is very unlikely to traverse more than an occasional mural pore. It is, therefore, only here and there in such a section that we should find the deficiencies in the walls of the corallites due to the presence of mural pores; and in some sections we might fail to find any traces of the pores. The only appearance which, so far as I know, could be confounded with the above is the apparent communication between two adjacent corallites seen in tubes of Chetetes, and of certain other types, as viewed in tangential sections. In these latter cases, however, it is not that two adjoining corallites are placed in communication by a perforation in their wall, but that one corallite is imperfectly separated into two by the extension into the visceral chamber of a septiform plate, the result of commencing fission. It is hardly possible for a practised observer to confound the appearances produced in this way with those due to the presence of mural pores; and in any case an examination of longitudinal sections would at once show the true nature of the phenomenon. 2. Vertical sections traversing the visceral chambers of the corallites. —Vertical sections of the Favositoid Corals—i.e. sections cutting the tubes longitudinally—usually in part traverse the visceral chambers of the corallites, while in part they coincide more or less closely with the walls of the corallites. In the former case, the section exhibits the infilling of the tube (calcite or mud), intersected by the tabulee and bounded laterally by the longitudinally divided wall of the corallite on each side (Fig. 1, 4’, B’, and C’). In such cases, the presence of mural pores can commonly be recognized by the more or less frequent occurrence of gaps or deficiencies in the wall on each side, the cavity of the tube being thus placed in communication with adjoining visceral chambers. The phenomena presented in these cases are precisely similar to those shown in tangential sections, and need no special notice. As in the latter, it is only here and there that the line of section happens to coincide with a mural pore, and it is, therefore, only here and there that we observe in long sections the gaps in the bounding-walls of the corallites caused by the presence of pores, the size and number of these gaps depending directly upon the size and number of the pores. As a rule, however, the presence of mural pores can in this way be readily recognized in thin vertical sections of Favosites, Michelinia, Pachypora, Alveolites, and the other Favositoid Corals (see Fig. 1). For obvious reasons, longitudinal sections which more or less closely coincide with the centre of the visceral chamber of a corallite cannot exhibit any signs of mural pores other than the gaps just mentioned in the bounding-walls of the tube. In other words, no trace of the mural pores can be found in the calcite or mud which occupied the space between the bounding-walls. It is not uncommon, however, to find certain structures in the calcitic infilling of the Prof. H. A. Nicholson—On the Favositide. 109. corallite which may readily be mistaken for mural pores. The struc- tures to which I allude present themselves as rounded dark dots arranged in lines, and presenting very much the appearance of being pores. In reality, these structures—which have sometimes been confounded by various observers (including myself) with mural pores —are the cut ends of septal spines or thorns, which project into the cavity of the corallite, and thus come to be divided in sections across the visceral chamber. 3. Vertical sections coinciding with the walls of the corallites.—As above mentioned, most vertical sections of the Favositoid Corals come here and there to traverse the walls of the corallites. This is inevitable when we reflect that the corallites are usually more or less curved, so that it is hardly possible for a vertical section to divide any single corallite along its whole length in a single plane. Hence, a section which in one place cuts a tube through the centre of the visceral chamber may in another place divide the same tube along one of its bounding-walls (see Figs. 1 A’ B’ and C’). When- ever the plane of a vertical section comes to coincide with the plane of the wall of a corallite, the mural pores are necessarily shown more or less extensively as round or oval perforations in the wall, the latter appearing as a more or less opaque space replacing the calcitic infilling of the visceral chamber (Fig. 1 A’). Almost all vertical sections of well-preserved examples of Favosites, Pachypora, Michelinia, Alveolites, etc., show the appearances here described at certain points ; and when this is the case, the presence of mural pores can never be doubted. In certain species of Favosites, however, as for example in F. aspera, D’Orb., and F. Mullochensis, Nich. and Eth. jun., vertical sections may fail to show the mural pores, owing to the fact that these openings are placed at the angles of the prismatic tubes, instead of along the flat faces of the corallites. In the species of Alveolites, also, owing to the position of the pores on the short sides of the corallites, vertical sections often fail to show the appear- ances just described, since the parts of the wall exposed in such sections commonly belong to the wide non-poriferous faces of the corallites. If an investigation of a coral otherwise similar to the Favositide should fail to bring to light any of the phenomena above described as indicating in thin sections the presence of mural pores, it may in general be safely concluded that such a Coral is ‘‘imperforate.” At the same time, it is not safe in all cases to conclude that mural pores are wanting merely because their presence has not been detected in one or two thin sections. There are plenty of cases where a single thin section exhibits no traces of mural pores, but where abundant evidence of the presence of these structures can be obtained by an investigation of a series of such sections. There are also cases where a specimen of a form certainly known to possess mural pores may nevertheless fail to show signs of these in thin sections, as the result of complete recrystallization or replacement. Such cases are, however, rare, and do not affect the general value of the characters above pointed out. 110 R. Lydekker—Tertiary Lacertilia and Ophidia. In conclusion, I may add that I have carefully examined a very extensive series of thin sections of the four types of Carboniferous Corals which Mr. Thomson speaks of as ‘the four species of Alveolites,” and I have failed to find in a single instance any indica- tion of any of the phenomena above mentioned as caused by the presence of mural pores. I have therefore no doubt that the corallites in these four types possessed imperforate walls; while the general structural features which they present render it certain that they are truly referable to the genus Chetetes, Fischer. TV.—Nortes on Tertiary LacertTILIA AND OPHIDIA. By R. Lyprxxer, B.A., F.G.S., ete. RECENT examination of the remains of Tertiary Lacertilia and Ophidia preserved in the British Museum having brought to light some new facts in regard to distribution, and also indicating the necessity of revision of certain determinations of other authors, I have thought it advisable to communicate the result of my observations in a collective form. Iguana.—In his description of the vertebrates of the Quercy Phosphorites Dr. Filhol’ describes and figures two fragments of the jaws of a small Lizard which he refers to the American genus Iguana, under the name of Iguana europeana, although in the description of the plate? they are mentioned as Proiguana. Among the Hastings collection from the Upper Eocene (Oligocene) of Hordwell in Hampshire I find several vertebrae (No. 32840, a) of a small Lizard, which show the minute zygosphenes characteristic of the Iguanas, and agree in all other respects with the vertebrae of existing forms. I have, therefore, no hesitation in referring these specimens to the Iguanide; and since (as I shall again have occasion to mention) at least a certain proportion of the Hordwell and Quercy Squamata appear specifically identical, I think it is not impossible that these specimens may belong to I. europeana. With regard, however, to the reference of this species to the genus Iguana, it will, of course, be necessary to use that term in a much wider sense than in recent herpetology, where it is restricted to two species; but if the type European form be eventually found decidedly different, the name Proiguana might be adopted. The occurrence of such an essentially American type in the European Tertiary is paralleled by the oc- currence in the CGiningen beds of the genus Chelydra among the Chelonia; and also of Latonia among the Heaudata, which is closely allied to, if not identical with, the Brazilian Ceratophrys. Placosaurus.—In his “ Zoologie et Paléontologie Frangaises,” 2nd ed. p. 260, pl. Ixiv. fig. 2, the late Prof. P. Gervais described and figured part of the cranium of a Lizard from the Upper Eocene (Lower Oligocene) of Vaucluse under the name of Placosaurus rugosus ; of which the most characteristic feature is the presence of an armour of sculptured polygonal dermal scutes on the upper surface. Many years later the same writer in his “ Zoologie et Paléontologie 1 Ann. Sci. Géol. vol. viii. p. 267. 2 Op. cit. p. 338. s R. Lydekker—Tertiary Lacertilia and Ophidia. 111 Générales,” sér. 2, p. 60, gave a woodcut of the cranial scutes of another Lizard from the approximately equivalent Phosphorites of Quercy under the name of Varanus margariticeps, making, however, no reference whatever to Placosaurus. Now if the type specimens of these two forms be compared together, there cannot, I think, be much hesitation in acknowledging their generic identity ; while it is perfectly clear from the presence of dermal scutes that they have nothing whatever to do with the Varanide. At a still later period Dr. Filhol* described and figured from the Quercy Phosphorites an imperfect dentary bone under the name of Palzovaranus cayluat, and suggested that it might be the same as the so-called Varanus margariticeps ; but since this specimen appears to belong to a true Varanus, it will be perfectly distinct from the latter. In the collection of the British Museum I find, however, a number of vertebree belong- ing to Lizards of medium dimensions, from Quercy (No. R. 428), and also others of similar type from Hordwell (No. 32840), which agree most nearly with those of certain existing genera of Anguide, and appear decidedly distinct from those of the Varanide, although there is a great general resemblance between the vertebrae of the two families. This would lead to the conclusion that since Placosaurus agrees with the Anguide in the presence of dermal scutes, the vertebra: in question belong to the Quercy species of that genus. I find, moreover, a dentary bone of a Lizard from Quercy (No. R. 3877) agreeing very closely with the dentary of the existing genera Diploglossus and Ophisaurus; and the presumption is therefore very strong indeed that this specimen is likewise referable to the Quercy Placosaurus. It appears, however, to be indistinguishable from a fragmentary dentary from Quercy figured by Dr. Filhol in pl. xxvi. fig. 425 of the work cited under the name of Plestiodon (= Humeces) cadurcensis; that genus belonging to the family Scincide. That the present specimen is, however, not a Scincoid is decisively shown by the absence of the descending ridge from the coronoid on the outer aspect of the posterior ex- tremity of the dentary, which forms such a characteristic feature in that family. Finally, on comparison of a Quercy femur (No. R. 387) with the similar specimen figured by Dr. Filhol (op. cit. pl. xxvi. figs. 445-446) under the name of Palgovaranus, I find a marked resemblance to the femur of the Anguoid genus Diploglossus and a wide difference from that of Varanus. The foregoing evidence tends therefore to show that all the above- mentioned specimens are in all probability referable to the genus Placosaurus; which accordingly appears to have been a member of the Anguid@g provided with well-developed limbs. There is no evidence to show whether the Quercy form is really distinct from the typical Vaucluse P. rugosus; but for the present it may perhaps be advisable to retain the specific name margariticeps, of which Plestiodon cadurcensis appears to be a synonym. ‘The Hordwell form may belong to either the Vaucluse or the Quercy representative of the genus, if these be distinct. And I may add that the North American 1 Op. cit. p. 268, pl. xxvi. fig. 434 (1877). 112 R. Lydekker—Tertiary Lacertilia and Ophidia. Kocene genera Saniva, Leidy, and Glyptosaurus, Marsh, are in all probability closely related to Placosaurus. Paleryx and Paleopython.—The genus Paleryx was founded in 1850 by Sir R. Owen’ on the vertebrae of a comparatively large snake from the Hordwell Beds, which was regarded as nearly allied to the existing genus Hryxz. In 1880 M. Rochebrune? described and figured certain Ophidian vertebra from the Querey Phosphorites under the new generic title of Palgzopython; identifying one species with Python cadurcensis of Dr. Filhol,* and naming a second species Paléopython Filholi. On comparing vertebrae from Quercy in the Museum (No. R. 428, a) which are indistinguishable from the speci- men figured by Rochebrune as Palgopython cadurcensis with the type vertebra of Paleryx rhombifer (No. 25259), I find that the two cannot be even specifically distinguished. Similarly I find that smaller vertebree from Quercy (No. R. 428, p) agree precisely with the types (No. 25261) of the Hordwell Paleryx depressus, Owen; and I believe that these are in all probability specifically identical with slightly larger Quercy vertebree (No. R. 428, c), agreeing with the type of Paleopython Filholi, Rochebrune. It appears, therefore, that the genus Palgopython is identical with Paleryx, and should accordingly be abolished ; but Iagree with M. Rochebrune in regarding the vertebree to which this name was applied as indicating a Snake very closely allied to Python, and clearly referable to the same family. Palezophis.—The vertebree of huge Serpents from the London and Bracklesham Clays, described by Sir Richard Owen in the memoir above cited as Palwophis, were regarded by him as allied to the marine Hydrophide. Other vertebre of similar structure were subsequently obtained from marine Eocene beds in North America, and described by Prof. Marsh under the name of Titanophis (Dinophis), although regarded by Prof. Cope as generically indis- tinguishable from Paleophis. Both these writers suggested that these Serpents were more nearly allied to the Pythonide than to the Hydrophide ; and in the memoir which I have already quoted M. Rochebrune came to the conclusion that they should be included in the Pythonide. If, however, the vertebre of Palzophis be compared with those of Python, it will be seen that they differ by their much taller neural spine, by the lower position and different contour of the costal articulation, by the much less prominent zygapophyses, by the more developed heemal carina, as well as in several minor features; and it would thus appear that on osteological grounds alone the reference to the Pythonide cannot be maintained. This inference is, however, supported by other considerations. Thus the existing Pythons are confined to the Old World and Australia ; and, although they can and do swim well in freshwaters, they are essentially land snakes. Judging, however, from the strata in which Palgophis and Titanophis occur, there is a very strong pre- sumption, as Sir R. Owen and Prof. Marsh have pointed out, that 1 Reptilia of London Clay (Mon. Pal. Soc.), pt. 3, p. 67. 2 Nouv. Archiv. d. Muséum, ser. 2, vol. iii. p. 277, pl. xix. 3 Ann. Sci. Géol. vol. viii. p. 270 (1877). Prof. E. Hull—Continental Lands and Oceans. 113 these Serpents were of marine habits; and the occurrences of closely allied, if not generically identical, forms on both sides of the Atlantic tends to confirm this view. In addition, therefore, to the osteological differences between Palcophis and the Pythonide, we have in all probability to add the difference of marine against terrestrial habits; and these two differences appear to me to leave little doubt as to the right of the former genus to represent a distinct family type—the Palgophide. There is, unfortunately, no skeleton of Hydrophis accessible to me for comparison with Palo- phis, but since M. Rochebrune states that the vertebrae of the former are widely different from those of the latter, I think, for the present at any rate, it will be advisable to retain the Palgophide among the true Colubriformes, where they may be placed after the Pythonide and allied families. In conclusion I may observe that figures of some of the specimens I have here mentioned will be given in the British Museum Catalogue of Fossil Reptilia and Amphibia, where attention will be somewhat more fully directed to the question of the specific identity of some of the forms to which I have alluded. V.—On tHe Erreot or ContinentaL LANDS IN ALTERING THE LEVEL OF THE ADJOINING OcEans.! By Professor Epwarp Hutt, LL.D., F.R.S., Director of the Geological Survey of Ireland. HE effect of the attraction of continental land upon the oceanic waters adjoining seems to have been very much overlooked by British physical geographers. That some slight effect arises in the direction of elevating the surface of the ocean in proximity to the coast is generally admitted, but the amount of rise is considered to be small, perhaps insignificant. The prevalence of these views was attributed by the author to the widespread influence of Lyell’s hypothesis of the uniformity of the ocean-surface all over the globe. The author’s attention had been called to the subject by the perusal of the works of the German geographers Suess’ and Fischer,’ especially the latter; and he had received great assistance in his investigations from Professor G. G. Stokes, M.P., Pres.R.S., and from the Rev. Maxwell H. Close, F.G.S., which assistance he gratefully acknowledged. In attempting to determine the relative levels of the ocean-surface along the margins of continents as compared with those of mid- oceanic islands, the German authors above quoted had based their results on observations of the length of the second’s pendulum. Many years ago (1849) Stokes had shown that the force of gravity must be greater in such islands than on continental stations,‘ and 1 The paper will probably be published im extenso in the Scientific Transactions of the Royal Dublin Society (1888). 2 Suess, Das Antlitz der Erde (1887). 3 Fischer, Untersuchungen tiber die Gestalt der Erde (1886). 4 Stokes, Cambridge Philosophical Transactions, vol. viii. pp. 672-695. DECADE III.—YOL. V.—NO. UII, 8 114 Prof. E. Hull—Continental Lands and Oceans. this conclusion corresponded with actual observations on the length of the second’s pendulum at stations all over the globe as tabulated by Airy.’ The formula of Suess and Fischer based on these was to the effect that the difference in the level of the ocean between two such stations was found in métres by multiplying the difference in the number of daily oscillations in the second’s pendulum by 122. This in the case of the stations of California (or Mexico ?) in lat. 21° 30’ and of the Sandwich Islands would amount to 4520 feet: a very startling result if correct. The author proceeded to discuss the effect of continental lands, showing that this was in the first instance divisible under two principal heads: The effect (1) of the unsubmerged, and (2) of the submerged masses. In the former case (i.e. where the mass rose above the surface), one component of the attraction acted in a more or less vertical direction ; in the second case, all in a lateral direction ; but both had the effect of elevating the surface of the ocean. The horizontal distance to which the vertical effect extended owing to the curvature of the earth’s surface was then considered ; and it was shown that, where continental lands rise from a deep ocean, the effect of the lateral attraction far exceeds that of the vertical attrac- tion of the unsubmerged mass. Professor Stokes had furnished the author with a hypothetical case, in which the elevation of the ocean was estimated to reach 400 feet above the mean geodetic surface of the earth. For the purposes of illustration three cases were selected, viz. :— (1) The table-land of Mexico, between lats. 18° and 26° N. (2) The table-land of Bolivia, us 19° and 26° S. (3) The Andes of Chile, i 26° and 35° 8. The mean elevations, distances from the ocean, and extent having been determined, and the mean density of the crust being taken at 2°6 for emergent, and 1:6 for submerged, land, the results of the attraction of the mountain masses in each case were as follows :— (1) Mexico, 280 feet; (2) Bolivia, 301 feet; (8) Chile, 63 feet; the elevations being calculated above a mean geodetic surface. To the above results, due to the gravitation-potential of the elevated masses, were to be added those due to the following factors :— (a) The marginal plain or emergent tract on either side of the mountain mass. (2) The high lands both to the north and south of the special sections above dealt with. (c) And lastly, and most important, the submerged continental mass. To provide for the sphericity of the earth deductions of various amounts, according to circumstances, were made from the numbers obtained from the formula which Mr. Close had arrived at by a double process, and which is given at length in the paper itself. Combining these results with those given above, we obtain as the whole rise of the ocean surface as follows :— (1) Mexico, 780 feet ; (2) Bolivia, 2159.feet; (3) Chile, 1582 feet. In all the above cases the coast was taken as descending to a 1 Airy, “On the Figure of the Earth,’’ Bncyclop. Metropolitana. W.S. Gresley— Variegated Coal-measures. 115 depth of 15,000 feet at a gradient of about 34; to =, the compara- tively low results in the case of Chile being due to the narrowness of the mountain range, 30 miles in mean breadth, as compared with 300 miles in the case of Bolivia. The above results, which are probably rather under than over estimates, fall considerably short of those to be drawn from Suess and Fischer’s formula, but are probably much in excess of the views held by British physical geographers generally ; and the conclusion was drawn, that if the same processes of reasoning and calculation were applied to all parts of the world, it would be found that the ocean waters are piled up to a greater or less extent all along our continental coasts, producing very important alterations in the ter- restrial configuration as compared with an imaginary ellipsoidal, or geodetic, surface, to which all these changes of level must necessarily be referred. VI.—Tue OccurreNcE oF VARIEGATED CoaAt-MEASURES, ALTERED TRONSTONES, ETC., AT SwWADLINCOTE, DERBYSHIRE. By W. S. Gresuzy, F.G.S. HIGHLY interesting and remarkable instance of altered Coal- measures, due to impregnation by hydrous and anhydrous oxides of iron, infiltrated by water from the overlying Permian strata, can now be seen in situ in the Ashby-de-la-Zouch Coal-field, and I think it should be made known in order that those who may wish to study such phenomena may have the opportunity of doing so. The following is a general description of the section. The section may be seen near the Fire-brick and Pipe Works of Messrs. Wragge, at Swadlincote, near Burton-on-Trent. The exact locality is where the words ‘‘ Round Wolds” occur half a mile east of Swadlincote, near bottom left-hand corner of Quarter-sheet No. 71 8.W. (Nottingham) of the One-inch Ordnance Survey. It is referred to on page 203 of Mr. H. B. Woodward’s new work on “The Geology of England and Wales.” It exhibits, in my opinion, 1. Four distinct systems or periods of strata, viz. Carboniferous, Permian, Trias, and Drift. Of the lowermost group of these rocks we have about 40 feet of Coal-measures, consisting of two thin coal- seams; four or five beds of fire-clay, three of which measure about 26 feet in the aggregate, and immediately below the Permians are variegated coal-shales with numerous nodules, and one or two bands of a variety of red hematite, and an occasional large concretionary mass of altered siliceo-ferruginous sandstone with cone-in-cone structure. The Permian strata appear to consist of dark red compact marl, some thin bands of tea-green marl, and a bed of semiconsolidated breccia, containing a variety of crystalline, slaty, igneous, and other rock-fragments.? Upon these lie yellowish soft sandstones, flaggy beds, marls, 1 See GrotocicaL Macazrne, No. 1, p. 17, January, 1887. 2 See GeoLocicat Magazine, Vol, for 18865, p. 333. 116 W. 8S. Gresley— Variegated Coal-measures. and a few quartz pebbles, and capping the whole is a rubble of sandstone fragments, layers of sand, a red marly clay with derived pebbles, and soil to surface. The total thickness of strata at present exposed is about 70 feet, but other beds come in, and can still be seen, between the variegated Coal-measures and the TBerantion) about 300 feet further to the north. Each of the above series lies unconformably upon the one beneath it; the Coal-measures have a north-easterly dip; the Permian beds dip east; the Trias lies nearly horizontal, and the Drift overlaps the whole, though it appears only locally. SECTION AT SWADLINCOTE, DERBYSHIRE. HH a2oooeococof Surface soil... Red clay, sand, and fr agments ‘of sandstone... Soft sandstone, with layers of yellow and red marl Yellow sandstone, with a few quartzite pebbles at base Light yellow sandstone ... Semiconsolidated breccia (sometimes i in two beds) | Green and red marly layers ... | Red marl, with greenish layers top and bottom ... wWrPnN OWrF ep 2 Permian Trias Drift { Highly-variegated argillaceous shale! with band and many flat fossiliferous nodules of red hematite, and a few large concretions | of yellow and red siliceo-ferruginous sandstone, exhibiting cone- in-cone structure, etc. ... 8 Dark blue shale without nodules, ‘but sometimes with red veins or joints Nee acs! dod i Odes) Lone! G0 ed0:! doo 3 Coal-seam—sometimes iridescent . Dark fire-clay ... as. < Lighter ditto—locally called “the marl”? .., Dark claysnane Strong grey dlocky fire- clay" the fire- -olay ” Hard dark shaly el i do Coal-seam... .. Inferior fire- clay Hard black clay .. Strong inferior fire- -clay With nodular ‘clay-ironstone ‘much wrinkled l OD SULLA CES HR Rese eul \AceHasane bet 2gN PEON es he aac me 8 ry Co eb CO “Ibo (or) WOWNOTAARACS S Coal-measures Floor of quarty, 2g sae ener. 50° Kieu (heacley | yseie due tsateniunm fl aamaaa O. Now, the principal wee of ntopoat in the abou section is the uppermost bed of the Coal-measures—the ‘bind’ or argillaceous shale with its accompanying concretionary ironstones and large balls of altered ‘cankstone.’ Where this stratum is in contact with the red beds of the newer rocks, its colour becomes entirely changed, and the great variety of hues of red, brown, purple, yellow, blue, etc., together with the often very curious and remarkably beautiful way in which the alternations, blendings and arrangements of form have been produced, is in itself quite a study. The ironstones, too, certainly deserve attention. When the shale is variegated or mottled, 1 Owing to unconformity the thickness of this stratum varies a good deal, and in places where the distance between the Permian marl and it, is much increased, the ironstone nodules are found in their natural condition (clay-carbonates). 2 The section not having been carefully measured, the thicknesses here given are only approximate. S. S. Buckman—Patleontological Nomenclature. a7 these are invariably found to be of a red haematite, more or less compact, and with the nuclei often of limonite more or less soft. These nodules of hematite were originally clay-ironstone before the Coal-measures were overlaid by the Permian beds. Of this I enter- tain no doubt, and in this very quarry may be seen the same nodules in their former condition. That these nodules in their normal state have a peculiar chemical composition not possessed by ordinary spheerosiderite of the Coal-measures seems highly probably from the fact that in weathering they sometimes become a deep red colour, and at others quite yellow. This alteration is always accompanied by a softening of the nodule, with reduction in weight. At a few yards to the south of the section given above, we find the red-staining from the Permian marl has extended to the Fire- clays beneath the 10-inch bed of Coal, giving them a somewhat similar variegated aspect (though the colouring is less vivid) to the shales above. The red hematitic character of the ferruginous nodules occurring in these clays shows also the change they have undergone since Carboniferous times. In this section too may be seen instances of faulting. We have a dislocation caused since the Triassic beds were deposited (where good examples of slickensides occur) ; also one in these beds but not descending to the Coal-measures—a small ‘doubling’ or overlap fault in the Permian marls, and contorted denuded surface of Coal- measures. The Coal-measures are highly inclined. It may be well here to note that some interesting examples of contorted coal and of ‘overlap’ faults are to be seen in the neighbouring open-hole work- ings to the south, notably in those of Messrs. Ensor & Co., The Pool Works, Woodville. Varieties of Coal-measure clays, and of the other clay-ironstone nodules, of ‘ peacock,’ or iridescent coal, and of Coal-measure fossils (marine? mollusca, coprolites, etc.), may also be obtained: in short, the section exposed probably exhibits as great a number and variety of geological and mineralogical details as could be found anywhere within so limited an area. There are within half a mile or so of this exposure several other interesting sections of some of the same beds, and of others besides, which could scarcely fail to repay a visit; but, as the excavations go on rapidly, and with strata lying so unconformable as these do, the geological details are always changing; in fact the variegated shale with hematite in Wragge’s section is rapidly thinning out, or else being obliterated by debris thrown back, or by land-slips. VIL.— PataontotocicaL NOMENCLATURE. By 8. 8. Buckman, F.G.S. {J\HE remarks made by Mr. Haddow in the Gronocican Macazine, Decade IIT. Vol. LIV. p. 519, seem to demand a reply. 1.—He complains of the multiplication of generic or subgeneric names of Ammonites. 2.—He laments the confusion which appears to have arisen concerning what have hitherto been regarded as recognizable species. 118 S. S. Buckman— Paleontological Nomenclature. 3.—He suggests that the trinomial system would obviate the necessity of any of these changes and be at the same time an advantage. In regard to the first point, I would remark that probably no change of any kind, however necessary. can be made without disturbing those who have been accustomed to other ways, and therefore, it is right that those who make these changes should give some reason for so doing. It can be urged that scarcely has the sound of the protests raised against the subdivision of the genus Ammonites died away, but the proposal to still further subdivide the subdivisions is started, and everything is again unsettled. But I would ask if paleontology is to follow, and be subject to, the same laws and conditions which govern other sciences, viz. entomology, botany, etc.? Is a genus to be considered as a name for a series of species having certain characteristics in common which at the same time separate it from other series? Is it not wrong to include in the same genus species descended for a long time through entirely different lines of ancestors? But do the present generic names satisfy these conditions? Does Harpoceras, which included such very different Ammonites as bifrons, insignis and Levesquet, 1.e. Ammonites descended from the old families Arietes, Armati, and Vatrices, of the Lias, fulfil the conditions of a genus? It cannot; and, therefore, I contend that it is necessary that the range of a genus should be narrowed. I place in the same genus Ammonites bifrons and Levisoni which agree in being very evolute, in having an identical suture-line, and quadrangular whorls with furrows on each side of a solid carina, but differ from each other specifically by a persistent but slight difference in ribbing. On the other hand, I decline to put into that genus Ammonites which have sagittate whorls, a different suture-line, and a hollow carina. As regards the difficulty of remembering all these names, I would point out that this is no more than we meet with in other sciences, and any disadvantage in this way is fully compensated by the advantage that we obtain by expressing a definite idea regarding a certain number of species. The number of genera in other sciences gives us sufficient excuse. For instance, in the division Geometers of the Lepidoptera we find, in Britain, about 200 species divided into 17 families and 88 genera. Concerning the second part of Mr. Haddow’s letter, I do not con- sider myself to blame for the confusion of which he speaks. He asks whether the “well-known specific names cannot be applied in a sufficiently comprehensive way to include the forms which the older authorities recognized under the names A. serpentinus, A. jurensis, and A. Sowerbyi, respectively ?”” But who are the older authorities in this matter? Surely they are those who in the first place imposed these names on certain definite species which they figured, and are we to perpetuate a mistake because since then certain authors and collectors have entirely mistaken the identity of the fossils so named ?. Mr. Haddow supposes, I fancy, that the species which the later authors had in view are merely varieties of what the older authors S. 8. Buckman—Paleontological Nomenclature. 119 had named, and that now there is “a tendency to confine a species within narrower limits than heretofore.” I contend, however, that this is not the fact, but rather that we are in possession of an increased number of new forms and an increased amount of know- ledge concerning their affinities and differences, and most certainly it is not the fact with regard to the species which he quotes. Am. serpentinus is not only not the same species, but so far as I can judge, not even the same genus as Am. falcifer. The large Ammonite figured as jurensis by Dr. Wright is not only most certainly not Zieten’s species, but is even characteristic of the Opalinum-zone. The name Ammonites jurensis has been the cause of some singular mistakes. I believe that it is an open secret that when Dr. Wright first visited the Dorset Inferior Oolite, and saw the large Lytoceras which I have since named Lyt. confusum, he mistook it for Am. jurensis, and there- fore classed the Inferior Oolite there as Lias, considering it to be on the same horizon as the Gloucestershire Cephalopoda-bed. Is not this an instance of the harm that can be done by extending the scope of a specific name? As to Am. Sowerbyi, it is none too easy to exactly determine what may be the adult form of the small specimen figured by Sowerby ; but nevertheless my experience is that the majority of Ammonites labelled Sowerbyi in our public collec- tions have but little to do with that species. When | first began collecting Ammonites, I found that all spinous falciform Ammonites of the Inferior Oolite were considered to be either Am. Sowerbyi, if with large coarse spines, or Am. variabilis, if compressed and with less conspicuous spines, and in fact the unfortunate meaning of the latter name was an excuse for placing any falciform Ammonites to that species that could not well be located elsewhere. ‘This was the method of “ general geologists,” and the species they so named had nothing at all to do with d’Orbigny’s Am. variabilis and but little with Am. Sowerbyi. What was the result? The ideas about the sequence of the Inferior Oolite beds and their correlation with those elsewhere were extremely indefinite, merely owing to a lax deter- mination of the Ammonites. Now I come to the trinomial system. Again I ask why should palzontological nomenclature differ from that of all other sciences ? Are we likely to get other sciences to change their now well-estab- lished nomenclature from the binomial to the trinomial system, and if not, why should paleontology desire to be peculiar? The binomial system has been used by it hitherto, and it would cause as much inconvenience to change to the trinomial system as it will to continue the binomial and without, I think, the same advantage. Quenstedt has used a trinomial and even a quadrinomial nomenclature, but in a haphazard way, and when we come to such a name as his Ammonites angulatus compressus gigas, it seems to me that we have done with both elegance and utility. A modified trinomial system is practically in general use for varieties, and may well continue so, as Ludwigia Murchisone, var. obtusa. But supposing that the name of a well-known Ammonite is to be used instead of the new generic names, I would ask Mr. Haddow to kindly arrange the following species under a trinomial system, viz. :— 120 Prof. J. W. Spencer—Ice Action in the North. Ludwigia Murchisone. bp 55 var. obtusa. cornu. or, Lioceras elegans. 99 opalinum. % 99 var. comptum. If he wrote Ammonites Murchisone, Am. Murchisone obtusus, and Am. Murchisone cornu, he would place Am. cornu in the same rank as the variety of Murchisone, which would not meet the facts of the case. If he leaves it Am. cornu, he does not show its relationship to Am. Murchisone, as I do by employing the word Ludwigia. ‘Then would he write Am. elegans, Am. elegans opalinus, and Ammonites elegans opalinus comptus? If so, I fancy the system would be a more cumbrous obstacle to a beginner than the employment of many generic names; but if he wrote Am. elegans comptus, he would not state the facts of the case, which are, that comptus is a variety of opalinus, not of elegans. Then, what rule would be followed with regard to choosing the Ammonite which should be the leading one of the group ? Surely that which selected the oldest known member, the one from which probably the others had descended, because an older species could hardly be placed subordinate to a younger one, which would happen by any other method. Therefore we choose elegans to be the dominant name, instead of using the new generic name Lioceras; but supposing we find a Ivoceras older than Am. elegans, and such a thing is not unlikely to happen, then we must again change the dominant name throughout the group. As regards the obstacles to beginners that these names present, I would remark that to them these changes do not present the same difficulty as they do to one who has been accustomed to an older system, and then has to unlearn and learn again. ‘The beginner, never having learnt an old system, does not find the new one more unfamiliar than the old. Besides which, the use of these generic names is intended to point out and emphasize the differences in Ammonites which are now passed over owing to their being grouped in such large numbers. Finally, with regard to the zones ; we have not reached perfection, and must effect changes of name as our knowledge increases. I, too, can point out a zone that is in danger, viz. the well-known Sauzet- zone, because it seems most probable that the Am. Sauzei, d’Orbigny, was previously figured as Am. contractus, Sowerby ; but d’Orbigny’s figure being so much more easily recognized, his name came into more general use. VIII.—Nores vron Icz Action 1x Hicn Latirupss. By Professor J. W. Spencer, M.A., Ph.D., F.G.S. ae notes are intended as an appendix to “‘ Notes on the Erosive Power of Glaciers, as seen in Norway” (vide this MaGazinuy, Decade III. 1887, Vol. IV. No. 4, p. 167). 1. The object of my visit to Norway and the Alps was to leave Prof. J. W. Spencer—Ice Action in the North. 121 closet-geology in America, in order to make personal observations of the phenomena associated with modern glaciers, —for comparison with those in the region of our Great Lakes, often attributed to land-ice. My conclusions—that simple land glaciers are not great eroding agents—are greatly strengthened, not merely by the observations of many other geologists, but particularly by those of various explorers in high latitudes—some of which are given here. 2. Herr Payer! states that the snow-line in Franz Josef Land descends to within 1000 feet of the sea (this is lower than is known anywhere else in the Arctic regions), and that numerous glaciers discharge great quantities of icebergs into the sea. He says :— “ However diligently I looked for them, I never saw unmistakable traces of grinding and polish of rocks by glacial action.” . 3. Lieutenant Lockwood? found in Central Grinnell Land a thick ice-cap extending for a distance of 70-90 miles or more, faced by an ice-wall of a nearly uniform height of 125-200 feet, irrespective of topographical inequalities. It was quite free from rock-débris, except in a valley confined by mountainous walls, thousands of feet high. Along its foot there was almost an absence of morainic ridges, and even where present these deposits were unimportant fragments. The general absence of rocks and dirt in the Arctic glaciers is com- mented on by General Greely, who observed them only in two or three glaciers. The glaciation about Lake Hazen was not recent. The snow-line in this high latitude of Central Grinnell Land is 3800 feet above the sea. 4, In Spitzbergen, with a lower snow-line, Baron Nordenskjéld * found striated rock-surfaces only below 1000 feet. The same holds good with regard to Labrador, where mountains rise 6000 feet, whilst the glaciation has not been observed above 1000-1600 feet (Dr. R. Bell).+ 5. In the Antarctic regions, the officers of the “Challenger” ° remarked the absence of débris in the icebergs seen ; although Ross in his Antarctic voyage examined volcanic rocks upon some of them. These volcanic blocks are supposed to have come from valleys in the mountains. 6. Indeed, outside the valleys, explorers in high latitudes have not found the tools for great erosion in the margins of the ice-caps visited. The continental area of North America presents much lower and less abrupt prominences than the reliefs of Greenland, Grinnell Land, Spitzbergen, or Franz Josef Land. Overhanging mountains seem to be necessary to furnish tools to land glaciers, by which alone any abrasion can be accomplished, and these conditions belong only to the valleys of great mountain ranges. 7. However, there is one condition, under which glaciers when shod with graving tools ought to be great eroders,—namely, when 1 « New Lands within the Arctic Circle,’’ 1872-74, Payer. 2 ««Three Years of Arctic Service,” 1881-84, Greely. 3 See GrotocicaL Macazine, 1876. 4 Hudson’s Bay Expedition of 1884. ° Notes by a Naturalist of the ‘‘ Challenger,’’ 1879, Moseley. 122 Prof. J. W. Spencer—Ice Action in the North. the motion is much more rapid than the flow of land-ice, which is three feet a day or less, and corresponds to the experimental move- ment—shown by Herr Pfaff,—under which conditions, as seen in Norway, included stones commonly adhere by friction to the subjacent rocks, and cause the lower surfaces of the ice to be grooved. Eixtraordinarily rapid movement has been seen at Jacobshavn glacier in Greenland, where Prof. A. Helland! found that the velocity reached 40-60 feet a day. In Alaska, Lieut. Schwatka? and Prof. G. F. Wright * observed a movement of 40-70 feet a day. In these cases the glaciers are moving into the sea, and a new element of partial flotation or sliding, which does not belong to the glaciers on land, is here introduced. The great velocity of these glaciers is far beyond any known ability of ice to flow asa plastic body. Con- sequently one is led to conclude that under partial flotation stones may be held firmly as graving tools by glaciers. 8. The appeal to the former magnitude of ice-masses as accom- plishing different results from those seen at present seems to be begging the question, for the action under a greater thickness would differ from that under a lesser, in amount rather than in kind, for increased pressure upon the ice—raising the temperature—increases its plasticity, as the general mass is not below freezing-point. Con- sequently it seems improbable that stones should be held firmly under the changed condition, for in addition to the increased plasticity, the friction between the stones in the ice, and the rock, is also increased by the greater weight of ice. 9. Over the vast area of action, the work of floating or sea-ice in some form, is enormous. On the northern side of Hudson Straits Dr. John Rae, who had very extensive Arctic experiences, found that snow, drifting over precipices into the sea, resulted in the formation of bergs 100 feet thick (filled with loose rock-débris of the coast), having the form of the shore where they were produced. Most of the bergs break loose and drift away to melt or become stranded elsewhere. 10. Greely describes the great momentum with which floebergs come together, and by their meeting, the ice is crushed and forced up into ridges 50 to 60 feet high. 11. One cannot carefully read the results of the last British Arctic Expedition of 1875-76, under Sir George Nares, without being impressed with the erosive power of drifting ice. Floebergs are pushed upon a shelving sea-bottom, until the ice has risen Z20—60 feet, after their first stranding, in perhaps only 48—72 feet of water, although of gigantic weight. As the grounded floebergs are forced up the shelving sea-bottom,. ridges of earth and stones are pushed up in front of them. Floebergs which have toppled over, thus showing their original bottoms, and also the pushed-up coast-ice, are found to be grooved and to contain angular stones with their exposed 1 See Q.J.G.S. 1877. 2 N.Y. Times Alaska Expedition, 1886. 3’ The Muir Glacier, Amer. Journ. Sci. 1887. # Canadian Journ, Toronto, 1859, Rev. A. Irving—Outlers on North Downs. 123 surfaces scratched and polished. As the movement is greater than the possible velocity of glaciers, it is only natural to expect great erosive effects from stones held as graving tools, or wrenched out owing to the brittleness of the ice, under such great stress, or from loose materials roughly thrust forward by the pack. 12. These observations and those of Prof. Milne’ in Newfound- land, and others upon the action of coast-ice, all confirm the cor- rectness of the verdict given by many geologists, especially in Hurope, who have had the opportunity of studying living glaciers, viz. that the potency of land-glaciers as great eroding geological agents is not proven, if indeed they operate at all in such a manner. IX.—Tertrary Ouriters on THE Nortu Downs. By the Rey. A. Irvine, B.Sc. (Lond.), B.A., F.G.S. i “Nature,” August 26, 1886, vol. xxxiv. p. 387, I ventured to draw a distinction between the outliers of unfossiliferous Tertiary sands found at high altitudes on the North Downs and the deposits containing casts of fossils of Pliocene age which are found in hollows in the Chalk at Lenham. Last summer I visited and examined, I believe, all the more important outliers of the former series, Mr. J. Hutchins French, F.G.S., having kindly conducted me to those at Headley and Chipstead; those at Netley were visited with other members of the Geologists’ Association under the direction of the same gentleman. The conclusion at which I have arrived from the lithological evidence (and there seems to be no other avail- able) is, that these sands are more probably of Bagshot age than of any other.’ There is a vast amount of reconstructed clay material capping these hills over many square miles, which, in colour and other characters, points to its original deposition as part of the Reading Beds, and in these unrolled Chalk flints are generally sparsely distributed. There are also a good many outliers of those beds mapped by the Survey on the higher parts of the North Downs.’ But there appear to be no traces of London Clay or of the Middle Bagshot clays. Of the unfossiliferous sands referred to, those exposed in the sand- pit in Chipstead Wood, and those seen in the pit on Netley Heath (where only one section occurs of undoubted Tertiary sands in siti, clearly differentiated from the overlying “run-of-the-hill” of later See Gronoctcat Macazine, Dec. Il. Vol. III. No. 7, p. 303, 1876. “ Nature,’ Oct. 16, 1887, vol. xxxvi. p. 531. Surely these are the patches of “‘clay-with-flints’’ (Argile a siler) of W. Whitaker and the French and Belgian geologists. —H. W.—The clays referred to are quite distinguishable from the ‘“ clay-with-flints’? of Mr. Whitaker and the Survey, if by that term is understood the insoluble residue frequently found on the surface of the Chalk, the calcareous constituents of the original rock having been dissolved away by carbonated atmospheric waters; a kind of deposit known to the French geologists as ‘“argile a silex”’ or ‘‘ terrain superficiel de la craie’’ (Memoir Les Causes Actuelles en Géologie, p. 306).—A. I. 1 2 3 124 Rev. A. Irving—Outliers on North Downs. date) are the exact counterpart in every way of the Upper Bagshot Sands, as these are seen in the interior of the district ; e.g. about Sandhurst, in the Fox Hills, and at Aldershot. Of those at Headley I should speak with more reserve as to their being Upper Bagshot, although I saw no good grounds for denying that they might repre- sent the more marginal facies of the beds of that group. There is rather more distinctness of bedding than usual, and the sands are rather less loamy, and more marked by colour-bands, as the result of subsequent infiltration. But this can be observed even in the highest beds of the Fox Hills in places, and elsewhere in the district. Associated with these sands on the Chalk hills at Headley, and in the debris of the hill-slope, well-rounded flint pebbles are met with in great numbers; at Headley they constitute a large proportion of the drift-gravel, which overlies the sands. These pebbles are so different from those which occur in the clays on the Downs, and so closely resemble the bluish Bagshot pebbles of Bearwood, Hast- hampstead, St. Anne’s Hill, Chertsey, Aldershot, etc., that it seems impossible to deny that they may belong to the same formation. Sarsens also are not infrequently met with. So far as the evidence goes, we seem (though it is not very strong) to have better grounds for assigning these outlying sands to the Bagshot (and perhaps to the Upper Bagshot), than any which has yet been brought forward for assigning them on the one hand to the Reading Beds, and on the other to the Pliocene.’ Assuming that they are of Bagshot age, and taking their present altitudes (550 to 600 feet above O.D.) into account, we arrive at the interesting and important result, that this represents approximately the extent of the post-Hocene elevation of the North Downs above the sea; and the differences between these and the present altitudes of the same horizons in the interior of the Bagshot area (if they could be precisely identified) would represent the extent of accentuation which the Wealden axis has undergone since the ocene period. The extensive prevalence of the Reading Beds to the south points to a later date for the elevation of the Wealden axis than that marked by those beds; while the presence of the pebbles in great force seems to indicate that the Chalk over the Wealden area was subjected to the abrading action of the sea to a large extent before the Hocene period” came to an end (as is well known) ; and to such an extent was this carried on, that even the Lower Greensand was exposed to the action of denuding agencies, and furnished a great part of the materials of the Upper Bagshot, in which scattered glauconitic grains occur locally. 1 See Mem. Geol. Survey, vol. iv. ® Exclusive of the Oligocene. Prof. J. F. Blake—Glaucophane in Anglesey. 125 X.—On THE OcCURRENCE OF A GLAUCOPHANE-BEARING Rock In ANGLESEY. By Prof. J. F. Buaxe, M.A., F.G.S. HE occurrence of glaucophane has not, I believe, been previously noted in Great Britain, and as it is a mineral of some interest, my friend Mr. Teall has suggested that a separate notice of it should be given. It would otherwise be naturally described in the Report on the Microscopic Structure of Anglesey Rocks to be presented to the British Association at their forthcoming meeting. The rock which contains the mineral in question has already, in a certain sense, been described by Prof. Bonney in the Quarterly Journal of the Geological Society, vol. xxxv. p. 3808, in the follow- ing words :— “XII. Quarry NEAR ANGLESEY Monument. “A foliated dense felted mass of a dull greenish, rather decidedly dichroic mineral (probably a species of chlorite), and of small greenish yellow epidote crystals, with a few angular fragments of quartz (?), and two or three scales of mica (? paragonite).” This description shows that the specimen which afforded it was one in which the glaucophane had gone over into chlorite, which it very frequently is found to do. In fact, there are many exposures of rock around the Anglesey Monument and to the south of it, which obviously, from their mode of occurrence and their connection with each other, all belong to the same mass, and their minute structure is of the same type; but in most the colouring mineral is a chlorite, and only in some of the freshest exposures, or in particular spots, is the original glaucophane seen. Elsewhere, by identity of structure and mode of recurrence, we may still recognize portions of the same mass in which the mineral is ordinary hornblende. These rocks have been hitherto taken to be identical with the dark schists of the district in which the prevailing mineral is chlorite, and only recently has Dr. Callaway, at the British Associa- tion, come round to consider some of them igneous. The beautiful blue tint of the glaucophane gives a very rich aspect to the rock under the microscope, by which the long crystals of this mineral are seen enwrapping and felting over the short crystals of epidote. The rock is so very foliated, in such excessively fine lines, and these are so beautifully contorted, that I had much difficulty at first in recognizing it as igneous; and since, according to my experience, hornblende in Anglesey is limited to igneous rocks, I had great difficulty in believing this blue mineral could really be glaucophane, which is only a variety of hornblende. However, I showed it to M. Renard at the meeting of the British Association, and he thought it would probably be glaucophane, and I therefore had a transverse section cut, and that set the matter at rest. Prof. Rosenbusch in his “ Mikroskopische Physiographie,” p. 471, gives the following as the characters of Glaucophane :— 126 Prof. J. F. Blake—Glaucophane in Anglesey. “Tt occurs always in prismatic crystals, bounded by the faces of coo P (100) and occasionally with o P & (010) or om P Z- (100), but without terminal faces. The usual cleavage is parallel to the prism with the amphibole angle (124° 25’—124° 44’), and the blue colour in reflected light makes it easily recognizable. Besides the cleavage, there is a very characteristic splitting, in which it particu- larly resembles actinolite. Glaucophane in the amphibole group corresponds pretty nearly with jadeite amongst the pyroxenes. The angle of extinction as measured on the plane of symmetry is very small, 4°—6°. The pleochroism is particularly clear and fine —c= sky-blue to ultramarine, rarely blue-green; 6 = reddish violet to bluish violet; a = nearly colourless to golden green. 8.G. = 3:0—38'1. Glaucophane appears to be entirely confined to the crystalline schists and phyllites. The paragenesis of glauco- phane is the same as that of actinolite and common hornblende, it is associated with diallage, omphacite, garnet, epidote, mica, and rutile.” The characters are perfectly possessed by the mineral in the Anglesey rock. It occurs in narrow elongated prisms, which are generally twisted round the epidote grains, and run into each other ; but in clear spaces, filled with quartz, some isolated narrow crystals appear, at least 8 times as long as broad, and appearing to die out like wedges at either end; in other words, they have no terminal faces. These prisms seen in polarized light without the analyzer are blue when their long axes are parallel to the principal, 7.e. the short axis of the Nicol, and nearly colourless when perpendicular. In ordinary light these of course produce a lighter tint of blue. As the mineral passes over into chlorite, this blue changes into green, as it may be seen to do in a single slide. As the long axis of a hornblende or glaucophane crystal les near to c, this blue is the characteristic one, and the colour seen in the perpendicular direction is a combination of the other two. When the prism is cut perpen- dicularly to its length, a rhombic section is seen. If the longer diameter of this rhombus, which corresponds to 6, is placed parallel to the principal plane of the Nicol, the colour is dirty violet; and if the short one corresponding to a is so placed, the crystal becomes colourless. With regard to the angles of this rhombus, its very small size, ‘004 in., in longer diagonal, and the uncertainty of the direction in which it may be cut, renders the observation not very close. But the acute angle in three distinct trials I estimated at 55°, 56°, and 55° 20’, giving a mean of 55° 27’, or for the obtuse angle 124° 33’, which is within the limits given by Rosenbusch. These are the usual forms, but in one case is seen a rhomboid whose obtuse angle was estimated at 125°, and which would therefore probably be obliquely cut, as shown also by one pair of sides being lengthened. and in this the acute angles are cut off by narrow planes making equal angles with the two sides. While therefore the rhombuses have their edges formed by 110, this shows the trace of the 010. I have not observed any crystal with the trace of 100. The lines of cleavage are parallel to the faces of the rhombus. With regard to the Prof. J. F. Blake—Glaucophane in Anglesey. 127 extinctions, when the long prisms are seen, they are either so matted together that no direction of edge can be ascertained, or they float in quartz, and no good extinction can be observed; but the darkest phase makes a large angle of about 15°, with the length of the prism. 4 2 > I5° si 4. ) oo Fic. 1.—Prism of glaucophane seen perpendicular to the longer axis ¢. Fic. 2.—End of the rhombic prism showing obtuse angle of 124°, Fic. 3.—Prism (110) modified by planes of the pinacoid (010). Fic. 4.—Showing plane of extinction making angle of 15° with the long axis of the prism. These observations leave no doubt that the mineral is glaucophane. Its associates are epidote, rutile (?), quartz, felspar (?), and calcite. The epidote is very abundant in small highly polarizing grains, so that the rock is actually a glaucophane-epidote rock. As epidote is chiefly characterized by its lime, and glaucophane by its soda, we may suppose that the rock is essentially a diorite, in which there would normally be a soda-lime felspar and a hornblende; but that either at its formation under peculiar circumstances, or by later alterations, the soda combined with the hornblendic ingredients to produce the variety glaucophane, while the lime caused epidote to be substituted for felspar. The rock is singularly free from garnets, though one patch may be this mineral. There are also a number of small prismatic-looking specks of a rich brown colour, which are some- times kneed, and which may possibly be rutile. These are the minerals essential to the rock; the others have been produced during the squeezings and stretchings to which it has been subject. Their interest lies in the fact that some of the crystals of glaucophane float freely in the clear crystalline substance, and the untorn substance does not look as if it could supply such crystals by tearing. It is thus suggested that the glaucophane as such may have been produced subsequently to the infiltration of the quartz. I have to thank my friend Mr. Teall for suggestions relating to this matter, and for taking the trouble to verify the determination of the mineral. 128 Notices of Memoirs—Dr. Eduard Brickner. WNOTLlCGmS OB MEMOLERS: oS I.—Guactation or Satzacn District. Dir VERGLETSCHERUNG DES SALZACHGEBIETES NEBST BEOBACH- TUNGEN UBER DIE Erszert In pER Scuwerz. von Dr. Epuarp Bruckner. Geographische Abhandlungen; herausgegeben von Dr. Atsrecat Pencx. Bd. 1. (Vienna, Hélder, 1887.) AD BRUCKNER’S paper on the glaciation of the Salzach district furnishes us with another chapter in the history of the Glacial period on the northern slopes of the Alps. Whilst previous writers, such as Al. Favre and Falsan, have traced out the develop- ment of the Rhone glacier of the ice period, and Penck has worked at the glacial deposits between the Lake of Constance and the Chiem Lake, the present author has chosen the district of the Salzach, further to the eastward, as the field of his observations, and has in this memoir accumulated a great amount of detailed evidence on the extent of the glaciation, its effects on the configuration of the surface and its recurrence at distinct intervals. ‘The results obtained agree with and confirm those of the authors above mentioned in the more westerly districts of the Alps. One very noticeable fact is the decrease in the intensity of the glaciation in passing from the west towards the east. This is well shown by the author in a table in which a comparison is made between the level of the upper surface and the thickness of the more important Alpine glaciers at their points of issue from the mountains, together with the respective distances and the levels to which they extended from the foot of the mountains and the width of their outer morainic areas. Thus, for example, the upper surface of the ancient Rhone-glacier at the position indicated was 1500 métres and its thickness 1300 métres; it reached 170 kilom. from the mountains, and descended to a level of 300m. The old Salzach glacier, on the other hand, was only 650 m. in thickness, and its upper surface 1050 m., whilst it only reached 52 kilom. from the mountains, and not lower than 500 m. The height of the snow-line in the Salzach district during the Glacial period is estimated at 1200 m. The author points out the very distinctive character of the two zones of ancient moraines; an outer, distinct petrographically as well as by its having a covering of Loess or of a fine clay of a similar character, and an inner moraine which has a well-marked terminal wall, and is without a layer of Loess. The author has ascertained the extension of the inner moraine over the Loess as well as over the outer moraine, thus indicating its interglacial age, and he has further discovered no fewer than seven profiles in which the two moraines were clearly separated from each other, either by the Loess, or by important beds of gravel and conglomerate, thus showing an interglacial interval between their deposition. The high terrace gravels which occur beneath the outer moraine, and the lower terrace gravels deposited in advance of the inner second moraine, are well developed in the Salzach district, and the author further describes Notices of Memoirs—Prof. Carvill Lewis— Matrix of Diamond. 129 a third series of widely-distributed gravels, which are believed to indicate a more extensive and an older advance of the glaciers. The character and origin of the lakes not only of the Salzach district, but of the Linth and those of the Neuenburg group, are fully treated, and a special chapter is devoted to the Glacial deposits of the Lake of Geneva. The text is accompanied by several figures and tables, as well as by three elaborate coloured maps of the district described. Il.—Tus Matrix or tae Dramonp. By Pror. Carvitt Lewis. (Abstract of a Paper read at the Manchester Meeting of the British Association, September, 1887.) MICROSCOPICAL study of the remarkable porphyritic peri- dotite which contains the diamonds in South Africa demon- strates several interesting and peculiar features. The olivine, forming much the most abundant constituent, is in porphyritic crystals, sometimes well bounded by crystal faces, at other times rounded and with corrosive cavities, such as occur in it in basaltic rocks. It rarely encloses rounded grains of glassy bronzite, as has been observed in meteorites. The olivine alters either into serpentine in the ordinary way, or into an aggregate of acicular tremolite crystals, the so-called ‘pilit,’ or becomes surrounded by a zone of indigo blue bastite—a new variety of that substance. The olivine is distinguished by an unusually good cleavage in two directions. Bronzite, chrome diallage, and smaragdite occur in fine green plates, closely resembling one another. The bronzite is often surrounded by a remarkable zone, with a centric pegmatitic, or chondritic structure, such as occurs in certain meteorites. This zone is mainly composed of wormlike olivine grains, but a mineral having the optical characters of cyanite also occurs in this zone. Biotite, a characteristic constituent, occurs in conspicuous plates, often twinned, generally rounded, and distinguished by its weak pleochroism, a character peculiar to the biotite of ultra-basic eruptive rocks. It alters by decomposition into the so-called Vaalite. Perowskite occurs in very numerous but small crystals, which optically appear to be compound rhombic twins. Pyrope is abundant in rounded red grains. Titanic iron, chromic iron, and some fifteen other minerals were also found. Rutile is formed as a secondary mineral through the alteration of olivine into serpentine, being a genesis of rutile not heretofore observed. The chemical composition shows this to be one of the most basic rocks known, and is a composition which by calculation would belong to a rock composed of equal parts of olivine and serpentine, impregnated by calcite. The structure is at the same time porphyritic and brecciated, being one characteristic of a volcanic rock which after becoming hard had been subjected to mechanical movements. It is a volcanic breccia, but not an ash or tuff, the peculiar structure being apparently due DECADE III.—VOL. V.—NO. III. 9 130 Notices of Memoirs—Prof. Carvili Lewis—Matrixz of Diamond. to successive paroxysmal eruptions. A similar structure is known in meteorites, with which bodies this rock has several analogies. A large amount of the adjoining bituminous shale is enclosed, and has been more or less baked and altered. The occurrence of minute tourmalines is evidence of fumarole action. The microscopical examination supports the geological data in testifying to the igneous and eruptive character of the peridotite, which lies in the neck or vent of an old volcano. While belonging to the family of peridotites, this rock is quite distinct in structure and composition from any member of that group heretofore named. It is more basic than the picrite porphyrites, and is not holocrystalline like dunite or saxonite. It is clearly a new rock- type, worthy of a distinctive name. The name Kimberlite, from the famous locality where it was first observed, is therefore proposed. Kimberlite probably occurs in several places in Hurope, certain garnetiferous serpentines belonging here. It is already known at two places in the United States: at Elliott County, Kentucky, and at Syracuse, New York; at both of which places it is eruptive and Post-Carboniferous, similar in structure and composition to the Kimberley rock. At the diamond localities in other parts of the world aihmonds are found either in diluvial gravels or in conglomerates of secondary origin, and the original matrix is difficult 76 discover. Thus, in India and Brazil the diamonds lie in conglomerate with other pebbles, and their matrix has not been discovered. Recent observa- tions in Brazil have proved that it is a mistake to suppose that diamonds occur in itacolumite, specimens supposed to show this association being artificially manufactured. But at other diamond localities, where the geology of the region is better known than in India or Brazil, the matrix of the diamond may be inferred with some degree of certainty. ‘Thus, in Borneo, diamonds and platinum occur only in those rivers which drain a serpentine district, and on Tanah Laut they also le on serpentine. In New South Wales, near each locality where diamonds occur, serpentine also occurs, and is sometimes in contact with Carboniferous shales. Platinum, also derived from eruptive serpentine, occurs here with the diamonds. In the Urals, diamonds have been reported from four widely separated localities, and at each of these, as shown on Murchison’s map, serpentine occurs. At one of the localities the serpentine has been shown to be an altered peridotite. A diamond has been found in Bohemia in a sand containing pyropes, and these pyropes are now known to have been derived from a serpentine altered from a peridotite. In North Carolina a number of diamonds and some platinum have been found in river sands, and that State is dis- tinguished from all others in eastern America by its great beds of peridotite and its abundant serpentine. Finally, in northern Cali- fornia, where diamonds occur plentifully and are associated with platinum, there are great outbursts of Post-Carboniferous eruptive serpentine, the serpentine being more abundant than elsewhere in North America. At all the localities mentioned chromic and Notices of Memoirs—Prof. Sollas—Geology of Wicklow. 1381 titanic iron ore occur in the diamond-bearing sand, and both of these minerals are characteristic constituents of serpentine. All the facts thus far collected indicate serpentine, in the form of a decomposed eruptive peridotite, as the original matrix of the diamond. T1].—Perrmian Fossits From SPITzZBERGEN. ANMARKNINGAR OM PERMFOSSIL FRAN SPETSBERGEN, AF BERNHARD Lunperen. Bihang till K. Svenska Vet. Akad. Handlingar. Bad. 18 (1887), Afd. iv. No. 1, pp. 3—26, t. 1. HE fossils from Spitzbergen which by de Koninck! and Geinitz were accepted as proving the Permian character of the beds in which they occurred, were shown subsequently by Lindstrém to be associated with species which, in other localities, are distinctly characteristic of the true Carboniferous Limestone, and the Spitz- bergen strata, in which this intermingling of Carboniferous and Permian fossils takes place, have therefore been termed the Permo- carbon series. In the Swedish expedition to this island in 1882, Nathorst and De Geer discovered in Belsund and Tcefjord a series of rocks, principally shales and sandstones, reaching a thickness of about 300 métres, which rests upon the thick mass of cherty and siliceous rocks of the Permo-carbon series, and are overlaid by rocks with Trias fossils. A scanty fauna, entirely marine, was found in this sandstone and shale series, and is described in this paper by Prof. Lundgren. It consists principally of small Brachiopods and Lamellibranchs with a single Coral, Stenopora columnaris, Schlot. Some of these forms are identical with, and others are closely allied to, those in the Permian series of England, Germany, Petschora-land, and the North-west of North America. In these Spitzbergen rocks all the fossils are distinctly of a Permian type, and the Carboniferous Lime- stone forms have quite disappeared, thus showing a gradual extinction of these latter before the deposition of this series, which may justly be regarded as Permian. Prof. Lundgren figures the new forms, which are of a dwarfed character. G. J. H. TV.—PRELIMINARY OBSERVATIONS ON THE GEOLOGY OF WICKLOW AND Wexrorp. By Professor Sotuas, LL.D., F.G.S. Q* rocks older than the Cambrian examples probably occur in the Carnsore district, but most of the presumed Archean rocks are to be explained as crushed igneous dykes and flows. The Cambrian are certainly unconformably succeeded by the Ordovician. The main granite of the district is a truly intrusive rock; but at its junction with the Ordovician which it penetrates, it possesses the characters of a true gneiss, the schistosity of which corresponds in direction with that of the adjoining schists, having resulted from earth-movements which took place after the Ordovician and before the Lower Carboniferous period. 1 Bull. de l’Acad. Royale de Belgique, ser. 1, vols. 13, 16. 132 Reviews— Prof. Osborn—On Mesozoic Mammals. SEVREG VL Ea Vis. —_@—__—. T.—On tHE STRUCTURE AND CLASSIFICATION oF THE Mrsozor1o Mammatta. By Dr. Henry F. Osporn. Proc. Acad. Nat. Sci. Philadelphia, June 21st, 1887. HIS paper is an outline of Professor Osborn’s observations “upon the structure of the British Mesozoic Mammals and a Classification of the Mesozoic Mammals in general, in view of their relationship to each other and to recent orders.” The author, who is well known by his numerous paleontological and morphological researches conducted in the Princeton College laboratories, has had the opportunity of examining the type-specimens of all the Mesozoic Mammals hitherto described, except four. The results of so extended a study are thus of unusual interest and significance. After some preliminary remarks, a series of notes are offered upon the English fossils, described by Owen; and the succeeding larger section of the paper is occupied with a general scheme of classification. Referring first to the Stonesfield Slate jaws, Dr. Osborn remarks that three distinct genera are commonly included under the name Amphitherium. The molar of Amphitherium proper (type A. Prevostit) is bicuspidate, with a low posterior heel; that of Amphitylus, gen. nov., has three blunt cusps and an internal cingulum ; while that of Amphilestes, Owen (type A. Broderipii), has three prominent cusps, and a pronounced cingulum, encircling the crown. The lower dental formula of Phascolotherium is given as 1. 4, c. 1, pm. 0, m. 7. Triconodon is the first Purbeck genus remarked upon. Dr. Osborn points out that in this primitive form, the fourth premolar early replaces a molariform milk-tooth, and the fourth true molar is very late in rising, thus agreeing precisely with the mode of succession determined by Professor Flower in certain existing Marsupials. Triacanthodon consequently becomes a synonym of Triconodon. Phascolestes is considered to be quite distinct from Peralestes, and Leptocladus from Stylodon. Spalacotherium has the lower dental formula, i.? 2, c. 1, pm. 4,m.6. The maxilla referred by Owen to Stylodon must be removed to a distinct genus, Kurtodon,' charac- terized by the compact arrangement and peculiar wearing pattern of the crowns, and a new enlarged figure is given in illustration. The maxillary formula of Bolodon is found to be i. ? 2, c. 0, pm. 3, m. 4, and the characters of these teeth are also shown in a woodcut. The following is a synopsis of the proposed classification :— I. Mutrirupercutata.—One incisor greatly developed at the expense of the others and of the canine; diastema, varying in width, in front of the premolars; molars characterized by two or more antero-posterior rows of tubercles separated by longitudinal valleys or grooves. Fam. 1. Plagiaulacide. Ctenacodon, Plagiaulax, Ptilodus. (Also the Tertiary Neoplagiaulax.) Fam. 2. Bolodontidse. Bolodon, Allodon. Fam. 8. Tritylodontide. Tritylodon. 1 Tn the original paper, the preoccupied term Athrodon is employed. This is replaced by Kurtodon in the ‘‘ Amer. Nat.,’’ Nov. 1887, p. 1020. Reviews—Prof. Osborn—On Mesozoic Mammals. 133 © JI. Szrconp Grovup.—Incisors numerous and sub-equal in size ; canines large ; usually no diastema ; premolar-molar series usually in excess of the typical number; molars cusped rather than tubercular. A. Jurassic Mammals. (i.) Carnivorous. Canines large, erect,; molars with strong internal cingulum; premolars with basal cusps; condyle of mandible low, and coronoid process broad. Fam. 1. Triconodontide. Triconodon (= Triacanthodon+ Priacodon), Amphi- lestes. (?) Amphitylus and Amphitherium. Fam. 2. Phascolotheride. TZvnodon, Phascolotherium. Fam. 3. Spalacotheride. MMenacodon, Spalacotherium. (ii.) Omnivorous. Lower canines large, erect ; molars with more or less prominent internal row of low cusps; condyle usually on or below the molar level. Fam. 4. Peralestide. Peralestes, Peraspalax. Fam. 5. Paurodontidee. Paurodon. Fam. 6. Diplocynodontide. Docodon, Diplocynodon, Enneodon, (?) Peramus. (iii.) Insectivorous. Incisors procumbent and spatulate ; canines small; molars without cingulum; condyle high, coronoid process slender. Fam. 7. Amblotheride. Achyrodon, Amblotherium. Fam. 8. Stylodontide. Stylodon (=Stylacodon), Aesthenodon, Laodon, Dryolestes, Phascolestes. (iv.) Herbivorous. Molars without cusps. Fam. 9. Kurtodontide. Kurtodon. B. Triassic Mammals (Protodonta, ? new order). Fam. 10. Dromatheride. Dromatherium, Microconodon. It is now generally admitted that many of the genera embraced in Cope’s Muurrrupercutata were Marsupials, and Dr. Osborn regards this group as most probably a suborder of the Marsupialia. The second group, however, is of a very different character, and Prof. Marsh has raised its Jurassic members to the rank of a new order [see Grou. Mac. July, 1887]. This arrangement presents some difficulties, and Dr. Osborn’s concluding remarks are devoted to these as follows:—‘It is impossible to find a single common character’ or set of characters for these genera which is of ordinal value. On the other hand, there are many grounds for placing the Triconodontide, Peralestidg, and Kurtodontide, and their affiliated families, in or near the ancestral lines of the modern Dasyuride and Phascolomyide respectively, while the Stylodontide are similarly related to the [Placental] Chrysochloride. These grounds may be partially stated. (1) Triconodon has one more premolar, but other- wise resembles Thylacinus both in the structure of the mandible and in the form and succession of the teeth. (2) Peraspalax, although much more imperfectly known, is allied to Dasyurus in its molar structure. (3) Kurtodon, although differing from Phascolomys in the possession of a large canine, shows a marked resemblance to this genus in the molar structure. . . . In the Amblotheride and Stylodontide we probably have a line of Insectivora. Dryolestes has 1 The mylohyoid groove is universally present, but is also found in Myrmecobius. 134 Reports and Proceedings— a molar pattern which is not observed in any Marsupial, but is seen in Chrysochloris among the Insectivora. Since, however, it is common for Marsupials to mimic the dentition of other orders, this relationship must be held with some reserve.” A 1S. Vee IJ.—DepartmMent or Mines, New Sovran Wates. (1.) Aynuat Report oF tHe Department or Mines, New Sour WALES, FoR YEAR 1886. Sypney, 1887. (2.) GroLoGy oF THE VEGETABLE CREEK Trn-Minine Freitp, NEw Eneiand District, New Sourn Waters. By T. W. Epcrworra Davin, B.A., F.G.8. Department of Mines, Sydney, 1887. HE annual report for the most part consists of details of the nature and amount of work carried on in the various mines of gold, silver, tin, copper, coal, and other minerals in different parts of the country, as well as of the character and prospects of the newly discovered mineral districts by the geological surveyors, under the direction of Mr. C. 8. Wilkinson, F.G.S., the head of the Survey. Of more than local interest is a report on New South Wales Diamonds, by Thos. Davies, F.G.S., and Robt. Etheridge, jun., in which, amongst other things, they point out that the diamonds from this country, in their physical characters are more nearly allied to those of Brazil than of any other country; that they are of greater hardness, which is a disadvantage as regards the cost of cutting, but on the other hand they are extra brilliant. The diamonds occur in drift which may be loose and coarse, and in places passes into a compact con- glomerate. This drift is due to fluviatile action at different geolo- gical periods. Thus there is no resemblance to the diamantiferous rock of the celebrated Kimberley mines of South Africa. Mention is made of the discovery of specimens of Mastodonsaurus in the Hawkesbury series at Cockatoo Island, and of a new species of univalve shell which is described by Mr. Robert Etheridge as Tremanotus maident, thus belonging to a genus hitherto only known from the Silurian rocks of North America and Europe. The form described is from the Hawkesbury sandstone, but there isa possibility that it may have been contained in a boulder of an older date. The volume on the Vegetable-Creek Tin-mining Fields, by Mr. Edgeworth David, gives a detailed account of the geological structure of the district accompanied by maps and sections. The tin-stone is met with principally in gravels, some of which are of Post-Tertiary age, whilst others are beneath massive beds of basalt and other eruptive rocks. The source of the tin-stone has been traced to veins in granite which occurs plentifully in the district. G. J. H. REPORTS AND PROCHHDINGS. We GroLocicaL Society or Lonpon. I.—January 25, 1888.—Prof. J. W. Judd, F.R.S., President, in the Chair.—The following communications were read :— 1. “On Ailurus anglicus, a new Carnivore from the Red Crag.” By Prof. W. Boyd Dawkins, M.A., F.R.S., F.G.S8. The specimen described is a small fragment of the right lower Geological Society of London. 135 jaw with the last three molar teeth in position, and belongs to the Crag collection of the Yorkshire Philosophical Society. It differs in a marked degree from all fossil European Carnivores, and presents no important points of difference when compared with a series of jaws of recent Ailurus. The author gave a description of the fossil and comparison of it with Ailurus fulgens, and also a table giving the comparative measurements of the teeth and jaws of the fossil and of recent Ailuri. The species from the Crag was a more powerful animal than any recent Ailuri in the British Museum. The paper concluded with a notice of the range of Ailurus in space and time. 2. “A Contribution to the Geology and Physical.Geography of the Cape Colony.” By Prof. A. H. Green, M.A., F.R.S., F.G.S. The account given in this paper of the geology of Cape Colony was founded on observations made during a visit to the country of four months’ duration for the purpose of reporting upon the coal. A considerable portion of the colony was traversed by the author, and, owing to the clear atmosphere and the barrenness of the surface, the rocks were unusually well seen. Much, too, had been ascertained by previous observers. The grouping of the South-African rocks adopted was the following :— Volcanic Beds, 9 d. Cave Sandstone, 9 ¢. 9. Stormberg Beds Bed Bedewoe! Molteno Beds, 9 a. . Karoo Beds. . Kimberley Shales. Great Unconformity. . Keca Beds. . Dwyka Conglomerate. Unconformity. . Quartzite of the Zuurbergen, Zwartebergen, and Wittebergen. . Bokkeveldt Beds. . Table-Mountain Sandstone. Great Unconformity. 1. Sa ae intrusive Granite of the neighbourhood of Cape Town (Malmesbury eds). Of the four lowest subdivisions very little was seen. The Bokke- veldt Beds had yielded fossils referred to Devonian. The detailed descriptions commenced with the Dwyka Conglomerate, which was coarse, containing both rolled and angular fragments, the matrix, which was ill bedded, resembling granitic detritus. Some of the boulders suggested doubtfully the action of ice. The Heca Beds consisted of hardened sandy clays, without lamination, and often weathering in spheroids, and resembling decomposed basalt or dolerite. These beds in the Ecca Pass, north-east of Grahamstown, were nearly 5000 feet thick. The Kimberley Shales were mainly grey and dark sandy shales, with a few thin layers of argillaceous limestone. At their base a conglomerate, resembling the Dwyka Conglomerate, was sometimes found. The Karoo Beds were red and purple shales, with buff or reddish sandstone containing much decomposed felspar. The Molteno Beds, also sandstones and shales, usually grey- and boo Pe og “Ic 136 Reports and Proceedings— dark-coloured, associated with grits and conglomerate, contained the only useful coals of the colony. These coals were peculiarly lami- nated and contained much ash; the seams were destitute of sand- stones and often eroded on the upper surface. These characters might indicate subaqueous origin. Owing to the irregularity of the seams, the views generally formed of the coal-resources of the colony may be exaggerated. The upper subdivisions of the Storm- berg Beds, the Red Beds, shales and sandstones of a red colour, the Cave Sandstone, a massive, fine-grained bed 150 feet thick, weather- ing white, and the bedded amygdaloidal lava-flows and tuffs that cap the whole, were but briefly noticed, as but few opportunities had offered for examining them. Some petrological details were given of the contemporaneous and intrusive traps, all appearing to contain the same constituents as the overlying subaerial traps, and doubtless belonging to the same series of volcanic outbursts. The author proceeded to review the lie of the rocks and physical structure of the country, distinguishing between the area of older rocks near the coast and the later deposits commencing with the Dwyka Conglomerate of the interior. There was apparently uncon- formity at the base of this conglomerate ; it and the overlying Hcca Beds were thrown into folds and occupied the Karoo Plains, whilst the ranges to the northward were formed of the higher beds, all nearly horizontal and resting quite unconformably on the Ecca Beds. These ranges had been carved out by denudation, which had removed the Molteno, Karoo, and Stormberg Beds to the south and north. The view advocated by Mr. Dunn that the Kimberley Beds north of the ranges represented the Ecca Beds to the south was discussed, and the author gave reasons for dissenting from it, and classing the Kimberley Beds as a higher subdivision. Some notes on more recent formations, the conglomerates of Oliphant’s River and superficial deposits, were followed by a summary of the author’s conclusions as to the probable geological history of South Africa. The Bokkeveldt Beds are shown by their fossils to be marine, and possibly all the formations up to the Zuurberg Quart- zite may be also marine. The Ecca Beds have yielded no fossils which would enable us to decide whether they are marine or fresh- water ; the Kimberley, Karoo, and Stormberg Beds are looked upon as lacustrine. 3. “On Two New Lepidotoid Ganoids from the early Mesozoic Deposits of Orange Free State, South Africa.” By A. Smith Wood- ward, Esq., F.G.S. Of the two species of fishes described in the present paper, one was founded on specimens of four individuals brought to England by Dr. H. Exton in 1888, together with the types of Tritylodon and Rhytidosteus, the other on two examples recently received from the same source. Both were from the Stormberg Beds of the Upper Karoo series. After giving further details of the structure of both forms, and describing the head and opercular fold, appendicular skeleton and Geological Society of London. 137 scales in each, the author showed that one species must be referred to the genus Semionotus, and was most nearly allied to the American types referred by Sir P. Egerton to Ischypterus. For this species the name of Semionotus capensis was proposed. The other species agreed in its characters with the Platysomide, and was especially allied to the genus Tetragonolepis ; but the nearest ally of all was a fish from the Hawkesbury Beds of Australia, Clithrolepis granulatus. The name of Clithrolepis Extoni was proposed for the new South African species. IJ.—February 8, 1888.—Prof. J. W. Judd, F.R.S., President, in the Chair.—The following communications were read :— 1. “On some Remains of Squatina Cranei, sp. nov., and the Mandible of Belonostomus cinctus, from the Chalk of Sussex, preserved in the Collection of Henry Willett, Esq., F.G.S., Brighton Museum.” By A. Smith Woodward, Esq., F.G.S. The remains referable to Squatina consist of a crushed skull, with the mandibular and hyoid arches, and an associated fragment of the pectoral fin with dermal tubercles. The fish was probably about 30 inches long. There are some difficulties in the way of interpre- tation, but the form and relative proportions of the cranium, etc., appear to be similar to those of the living representative of the genus. The dentition is not completely preserved; the teeth near the symphysis of the mandible are relatively high and slender, while the opposing teeth are small. The great relative size of the spinous dermal tubercles serves to distinguish it from species of Squatina already known. The anterior lower teeth are also more slender than in the existing S. angelus. No specimen of Belonostomus has hitherto revealed the precise characters of the dentition or the relations of the hindermost bones. This deficiency is now supplied. The two rami occupy only one half the entire length of the jaw, the anterior half being formed by the elongated presymphysial bone, which is provided with a powerful prehensile dentition. The character of the teeth was described by the author: the large median teeth end abruptly at the posterior extremity of the presymphysial element, but the small lateral teeth are continued backwards upon the rami of the jaw, increasing in size and becoming relatively shorter. Further details were given, and the evidence shows that the original specimens described by Agassiz, as portions of the mandibular rami of Belonostomus cinctus, are really fragments of the presymphysial bone of this species. Some of the relations of Belonostomus and Aspidorhynchus were pointed out. 2. “On the History and Characters of the Genus Septastrea, D’Orbigny (1849), and the Identity of its Type Species with that of Glyphastrea, Duncan (1887).” By George Jennings Hinde, Ph.D., ¥.G.S. D’Orbigny founded the genus Septastreea on the characters of a coral from the Miocene strata of Virginia, which was named S. sub- ramosa, but no specific description was given. In the same year (1849), Edwards & Haime accepted the genus as valid, but placed 138 Reports and Proceedings— S. subramosa as a synonym of Astrea ramosa, Defrance—an appa- rently recent species of coral which had previously only been informally described by Defrance. They also included in the genus S. Forbesz, the original specimen of which was from the Miocene of Maryland, and at that time in the collection of the Geological Survey in London. Later on, in 1852, D’Orbigny claimed that S. Forbes was but a synonym of his S. subramosa. There is good reason for regarding this as correct, but owing to the fact that D’Orbigny’s name subramosa was merely nominal and without description, the later name of S. Forbesi, Edwards & Haime, must be allowed to. stand for the type of the genus Septastrea. In 1861 de Fromentel, and in 1867 Prof. Duncan, included in Septastrea several species of Jurassic and Liassic corals, which, however, have no generic relationship to the type form of the genus. from the Miocene Tertiary. In 1887 Prof. Duncan read a paper before the Geological Society, in which he adopted Septustrea Forbesi, H. & H., as the type of a new genus Glyphastreea, thus leaving in Septastrea those Liassic and Jurassic species placed therein by himself and de Fromentel. As this proceeding is contrary to recognized rules of nomenclature, the genus Glyphastrea will have to be abolished. In the type form of Septastrea, now in the British Natural- History Museum, the walls of the corallites, though closely apposed, are quite distinct ; the theca is formed by the extension of the septal laminz; the walls and septa in the lower portion of the corallites. are very thin, but the upper portion of the corallites are so infilled with compact stereoplasm that the calices are extremely shallow when mature. There is no true columella, only a pseudo-columella, formed by the union and partial involution of the inner septal margins. The increase is inclusively by marginal gemmation; fission does not occur. In some cases linear perforations between the septa are shown; these appear to be for the insertion of the mesenterial muscles. Tha septa in Septastrea consist of a central layer, dark in micro- scopic sections, the primary layer of v. Koch or centre of calcifica- tion of Bourne and Fowler, enclosed on both sides by layers of compact subcrystalline stereoplasm. In longitudinal fractures the septa frequently split in the centre of the dark or primary layer, and thus show that each half of the septum consists of a dark and light portion, and the median face of each septal lamina exhibits. transverse growth-lines, not unlike those of an epitheca, beneath which are delicate longitudinal ridges and grooves. The thecal wall has a similar structure to that of the septal lamine, of which it is. an extension. There is a close correspondence in the septal and thecal structure- of Septastr@a to that of the recent and fossil genus Flabellum, and in this genus also the septa occasionally split longitudinally and show the same growth-lines on their median faces. Only two species are included in Septastrea, as now defined, viz. S. Forbesi, H. & H., and S. (Columnaria?) sexradiata,. Lonsdale, sp. Geologists’ Association. 139 - 3. “On the Examination of Insoluble Residues obtained from the Carboniferous Limestone at Clifton.” By E. Wethered, Hsq., F.G.S. The author noticed previous classifications of the Carboniferous Limestone at Clifton, and submitted the following for reference in the present paper :— CARBONIFEROUS LIMESTONE SERIES. feet SiacenC HU ppermMsimestonesirececceactccscececscessoesecweresecctres ceases 100 Middle nGimestonesieecreneceswesiersecesesisiaceccscccisallessio elses 1620 », A. Lower Limestones :— MB ack vO CKiwirascicsk cslccaccecescscweenbeosete 490 2. Lower-Limestone Shales.............s20000++ 500 — 990 Motallpcictskvaweesevcees 2710 The limestone-forming organisms in each of the above were mentioned, and the methods adopted for obtaining the insoluble residues by means of hydrochloric acid were described. A table of percentages of insoluble residues was given from the Lower Lime- stone Shales and Black Rock, from the Oolitic Beds, Mitcheldeania- beds, and main portion of the Middle Limestones, and from the Upper Limestones. Detrital quartz of small size, with a few grains of felspar, tour- maline, and zircon, characterize the Lower-Limestone Shales, and in one variety the soft tissues of organisms are represented by ferric oxide, which in the case of crinoids represents the whole skeleton. Residues of the Black Rock exhibit slight secondary crystallization round detrital quartz, whilst amorphous and chalcedonic silica become more plentiful. Residues of the Middle Limestone consist to a less extent of detrital quartz along with micro-crystals of quartz, amorphous and chalcedonic silica, and less frequently of pyrites, tourmaline, and zircon; sponge-spicules are also noted. Towards the top of the Middle Limestones the proportion of detrital quartz increases, and the deposit of secondary silica on the surface of quartz-grains is less marked. ’ The nature of the amorphous and chalcedonic silica in the lime- stone, and the relations of this silica to the small quartz-crystals, were also discussed. The latter were shown in some instances to possess nuclei of detrital quartz, and where this is not the case, to have resulted from the crystallization of amorphous silica. GeoLocists’ ASSOCIATION. December 2nd, 1887.—F. W. Rudler, Esq., F.G.8., President, in the Chair.—The following communication was read :— «A Synopsis of the Vertebrate Fossils of the English Chalk,” by A. Smith Woodward, F.G.S., F.Z.S. The author reviewed in succession the various genera of fossil vertebrata hitherto recorded from the English Chalk, adding full references to the literature of the subject, British and Foreign. A careful examination of the type-specimens and numerous other fossils in the British Museum, Brighton Museum (Willett Collection), 140 Reports and Proceedings— Woodwardian Museum, the Museum of Practical Geology, and the private cabinets of Mr. 8. J. Hawkins, F.G.S., and other members of the Association, had suggested several emendations in the already accepted nomenclature of the genera and species, besides adding a few new forms, either now described, or deferred for description to a future occasion. The revised list is as follows, with synonyms in brackets :— REPTILIA. Order CuELonia. (?) Chelone Hoffmanni. [ Chelone Camperi, Owen. | Cimoliochelys Benstedi (Mantell), Owen. [| Emys. Benstedi, Mantell. | Order SAUROPTERYGIA. Polyptychodon continuus, Owen. a interruptus, Owen. Plesiosaurus Bernardi, Owen. ‘ constrictus, Owen. Bp Smithit, Owen. Order IcHTHYOSAURIA. Ichthyosaurus campylodon, Carter. Order PyrHonoMoRPHA. Mosasaurus anceps (Owen). [Leiodon anceps, Owen. Mosasaurus stenodon, Charlesworth. ] Order Lacerri.ia. Dolichosaurus longicollis, Owen. Coniosaurus crassidens, Owen. Rhaphiosaurus subulidens, Owen. [R. luctus, Owen. | Order PLEsIosauRIA. Ornithocheirus giganteus (Bowerbank). [ Pterodactylus giganteus, Bow., Cimo- liornis diomedeus, Owen, Pterodactylus conirostris, Owen. | 99 Cuvier (Bowerb.) [Pterodactylus Cuviert, Bowerb.] 99 compressirostris (Owen). [Pter. compressirostris, Owen. | PiscEs. ‘Order Sexacutt. Acrodus (?) Illingworthi, Dixon. [? Hybodus.] Corax faleatus, Agass. [Corax maximus, Dixon.] »» pristodontus, Agass. ft Drepanephorus major (Agass.), Egert. [Spinax major, Agass., Cestracion canaliculatus, Egert., Drepanephorus canaliculatus, Kgert., Acrodus eretaceus, Dixon, (?)Acrodus rugosus, Agass.] Hybodus dubrisiensis, Mackie. Notidanus microdon, Agass. 99 pectinatus, Agass. Odontaspis rhaphiodon, Agass. ae subulata, Agass. Otodus appendiculatus, Agass. 9 erassus, Agass, », semiplicatus, Minster. Oxyrhina crassidens, Dixon. Re Mantelli, Agass. [Lamna acuminata, Agass.] Piychodus decurrens, Agass. [ Ptych. depressus, Dixon.] a latissimus, Agass. [Ptych. paucisulcatus, Dixon. ] HY mammillaris, Agass. [Ptych. altior, Agass. ] a Owent, Dixon. 39 polygyrus, Agass. [Aulodus Agassizii, Dixon, Ptych. latissimus, Agass. in part.] 9 rugosus, Dixon. [Ptych. altior, Dixon, non Agass.] Scylliodus antiquus, Agass. Squatina Cranet, A. S. Woodw. Geologists’ Association. 141 Order CHIM#@ROIDET. Edaphodon Agassizii, Buckl. %6 crassus, Newton. a gigas, Kgert. a Mantellit, Buckl. 3 Sedgwickii, Agass. Elasmodectes Willetti, Newton. [EHlasmognathus, Newton non Gray.] Ischyodus brevirostris, Agass. (var.) A incisus, Newton. Order GANOIDEI. Belonostomus attenuatus, Dixon. cinetus, Agass. Ceelodus angustus (Agass. ), Zittel. [Gyrodus angustus, Agass.] a Cietacaus ee Zittel. [Pycnodus cretaceus, Agass. | », (?)faba (Agass.), Zittel. | Acrotemnus faba, Agass. | A ay allelus ((Dixon), Zittel. [ Pycnodus parallelus, Dixon. | Gyrodus cretaceus, Agass. [Gyrodus conicus, Dixon. ] Lophiostomus Dixoni, Egert. Macropoma Mantelli, Agass. [Aimia ? lewesiensis, Mantell.] Microdon (?) occipitalis, Dixon. Neorhombolepis excelsus, gen. et sp. Nov. Prionolepis angustus, Kgert. Gen. non det. [Lepidotus punctatus, Agass. MS. ] Order TELEOSTEI. Acrognathus boops, Agass. Aulolepis typus, Agass. Berycopsis elegans, Dixon. Beryx radians, Agass. » (?) microcephalus, Agass. Calamopleurus anglicus, Dixon. Cimolichthys levesiensis, Leidy. [Saurodon Leanus, Agass. non Hays.] Cladocyclus levesiensis, Agass. Daptinus intermedius, Newton. Dercetis elongatus, Agass. Enchodus levesiensis (Mantell), Agass. [Esow lewesiensis, Mantell, Enchodus halocyon, Agass.] Homonotus dorsalis, Dixon. Hoplopteryx levesiensis (Mantell). [Zeus lewesiensis, Mantell, Beryx ornatus, Agass. | superbus (Dixon). [Beryx superbus, Dixon. ] Ichthy yodectes elegans, Newton. x minor (Dixon), Newton. [Hypsodon minor, Pen Osmeroides levesiensis (Mantell), Agass. [Salmo lewestensis, Mantell. ] 99 (?) erassus, Dixon. Pachyrhizodus basalis, Dixon. 5 Gardneri (Mason), W. Davies MS. [Hypsodon lewesiensis, Ag., in part, erroneously described and figured. “Acro- dontosaurus Gardneri, Mason. ] gracilis rere W. Davies MS. [Mosasaurus gracilis, Owen.] Plata nuchatis (Dixon), A. 8. Woodw. [Jicrodon nuchalis, Dixon.] Plethodus expansus, Dixon. a oblongus, Dixon. Plinthophorus robustus, Giinther. Pomognathus eupterygius, Dixon. Portheus Mantelli, Newton. [Hypsodon lewesiensis, Agass. in part. ] », Dawviesii, Newton. 49), Sp: ind: [Hypsodon lewesiensis, Agass. in part. | Protosphyrena ferox, Leidy. [Saurocephalus lanciformis, Agass., non Harlan. Xiphias Dixoni, Leidy. Erisichthe Dixoni, Cope. ] minor (Agass.), A. S. Woodw. [TZetrapterus minor, Agass.] Saurccephalus (?) striatus, Agass. Stenostoma pulchella, Dixon. Stratodus anglicus, sp. noy. 142 Correspondence—Mr. T. MW. Reade—Mr. Clement Reid. Tomognathus mordax, Dixon. [ Lom. lecodus, Dixon. ] Elopine Clupeoid, gen. non det. Incert# SEDIS. Celorhynchus cretaceus, Dixon. Ancistrodon, sp. Pelecopterus spectabilis (Agass.), Cope. [Ptychodus spectabilis, Agass. | 48 gibberulus (Agass.), Cope. en gibberulus, Agass. | ui arcuatus (Agass.), Cope. 46 arcuatus, Agass. | ‘5 (?) articulatus (Agass.), Cope. [- ,, articulatus, Agass.] The author also pointed out that the type specimen of Strophodus asper, Agass., is a fragment of a Orustacean; that the so-called Orthagoriscus-jaw (Dixon) is the dentary bone of a Chelonian; that Selache Daviesii, Hasse, is founded upon a vertebra of Ptychodus ; and that the so-called premaxilla of Enchodus is really the palatine bone. CORRESPONDENCE. a THE DIMETIAN OF ST. DAVIDS. S1r,—The geology of St. Davids will, I fear, never be settled by petrological methods. Recognizing this, I based my interpretation of the so-called Dimetian principally upon the relation and disposition of the various groups of rocks composing the peninsula of St. Davids. The result of my examination was to lead me to believe that by no known system of faults and folds could the “ Dimetian,” if a pre- Cambrian body, have been placed in its present relations with the surrounding rocks. This is my main contention, and all the remain- ing arguments are subsidiary, and in value only relative. As I have already developed these views in detail in a paper just read before the Liverpool Geological Society, I need not further dwell upon them here. It is very far from my intention of entering upon a controversy upon this question, most of all from a petrological standpoint. On a re-perusal of the literature on this subject, I find that Dr. Hicks formerly described as shales interbedded in the Dimetian what he now considers to be Diabase Dykes. I may be quite wrong in my view that the veins in question are included Cambrian shales; but until I have an opportunity of re-examining the district, I am not prepared to admit his contention. Parxk CornER, BLUNDELLSANDS, T. Mretiarp Reape. 11th January, 1888. THE EXTENT OF THE HEMPSTEAD BEDS, Etc. Sir,—Writing in the Isle of Wight,’ with no library available, I find I have overlooked a paper by Dr. E. P. Wilkins, F.G.S. As long ago as 1861 he recorded a section of Hempstead Beds in the Medina (see Proc. Geol. Assoc. vol. i. p. 194). Ciement ReErp. 1 Grou. Mac. Nov. 1887. Obituary—Dr. F. V. Hayden. 143 MISCHIMANHOUS British PrerroGRapHy. Ir may interest our petrological readers to learn that the remaining portion of Mr. Teall’s admirable “ British Petrography” is in the press, and will shortly appear. The issue in monthly parts, as originally contemplated by Mr. Teall, had, in consequence of an unforeseen contingency, to be discontinued. The firm of publishers that had undertaken to bring out the work became involved in financial difficulties, and ultimately failed, placing Mr. Teall in the remarkable predicament of having to purchase a portion of his own book. We are happy to be able to state that the work is now in good hands, namely, those of Messrs. Bemrose & Son, and is only awaiting the completion of a few of the plates, before being given to the scientific world. We must congratulate the author on having brought to a favourable conclusion an undertaking as comprehensive in design as it is thorough in execution. The 200 pages which have already appeared, replete with accurate and minute description, well furnished with references to original sources and illustrated by plates of surpassing beauty, have been sufficient to place the book in the front rank of petrographical literature, among such classic compeers as Fouqué and Lévy’s “Minéralogie Micrographie,”’ Rosenbusch’s «« Physiographie der Mineralien und Gesteine,” and Zirkel’s “ Lehr- buch der Petrographie.” (GS LIE OPP NS Nae FERDINAND V. HAYDEN. Born SEPTEMBER, 1829; Diep 23rp DrcemBer, 1887. Dr. F. V. HaypEen was born in Westfield, Mass., in 1829. He was a graduate of Oberlin College, Ohio, and received the degree of Doctor of Medicine from the Medical School of Albany, N.Y., in 1853. He was surgeon in the army during the civil war ; and after it for seven years, he held the position of Professor of Mineralogy and Geology in the University of Pennsylvania. But the larger part of his time, from 1858 to the close of 1878, an interval of twenty-six years, was spent in Rocky Mountain explora- tion, in which his special work was geological; and through his labours and the investigations of those associated with him, a wide extent of territory, until then little studied, was examined geologi- cally and topographically. Coal-beds were found and a new coal- flora made known, new fossil Mammals, Reptilia, and Fishes, in great numbers, were collected and described, the stratigraphy and paleontology of the Cretaceous and Tertiary and the intermediate Laramie or Lignite beds were well investigated, and the Yellowstone Geyser region brought to notice and explored. Dr. Hayden’s personal work consisted in a general geological reconnaissance of the regions visited, the collection of fossils, which was the chief object of the earlier expeditions, and the supervision and direction of the surveying parties. He was the first to make known the facts as to the vast Tertiary lake-areas of the summit 144 Obituary—Dr. F.. V. Hayden. region and eastern slopes of the Rocky Mountains, whence he drew the conclusion that the elevation of the mountains went on slowly through the whole Tertiary, commencing with the Laramie, which afforded some brackish-water fossils. His first two expeditions were made in 1853 and 1855 to the Bad Lands on White River, in Dakota, that of 1858 at the expense of Professor James Hall. Large collections of remains of fossil mammals were brought home, besides numerous other species. His paleontological friend, Mr. F. B. Meek, was with him. In 1857 he accompanied Lieut. G. K. Warren’s expedition, and made the discovery of the rich Niobrara Mammalian fauna, newer than the White River, and obtained a great number of specimens. In 1866 he visited the ‘“‘ Bad Lands,” making collections for the Academy of Natural Sciences of Philadelphia. The mammalian remains obtained in these various expeditions, along with those gathered by Dr. John Evans in 1849 and 18538, and Mr. Culbertson 1850, were the materials used by Dr. Leidy for his great work on the Extinct Fauna of Dakota and Nebraska (1869). During 1859 and 1860, Dr. Hayden was connected, as geologist, with Capt. Raynold’s expedition to the headwaters of. the Yellow- stone and Missouri. In 1867, after the civil war, the series of government expeditions under his charge was begun that continued through the consecutive years to the close of 1878. By these expeditions his explorations became extended over large parts of Nebraska, Dakota, Colorado, Utah, Wyoming, Montana, New Mexico, and Kansas. The first appropriation was only 5000 dollars ; but the later were more liberal, and besides his regular corps, a number of other scientists sometimes accompanied the exploration. Mr. Meek accompanied him, and through him large numbers of invertebrate species of the Cretaceous, Tertiary, Jurassic, and other formations were figured and described; and precision was thus given to the facts for success in Jaying down the subdivisions of these formations and mapping their distribution. After the death of Mr. Meek in December, 1876, his department passed under the charge of Dr. C. A. White. Mr. L. Lesquereux investigated, figured and described the fossil plants of the Laramie and other formations. Dr. Cope joined the expeditions of 1872 and 1878 and afterwards described the vertebrate fossils, collected in these and later years, in two quarto volumes. The many volumes of the expedition, in 8vo. 4to. and the atlases, need not here be enumerated. Dr. Hayden had reason for feeling eratified with the great scientific results obtained by the expeditions under his charge, and the wonderful discoveries made concerning the ancient life of the continent, its vast mineral resources, and the successful mapping of its topographic features. Since the expedition closed in June, 1879, Dr. Hayden has resided in Philadelphia. Dr. Hayden was a member of the National Academy of Sciences, and received various honours from academies abroad. He was elected a Foreign Member of the Geological Society of London in 1879.—Silliman’s Amercian Journal. Geol.Mag.1888. Decade II] Vol. V.PI.VI. aa F.C Ken gint Lith, West,Nevanan &Co1mp, ° Scandinavian Phyllocarida. THE GEOLOGICAL MAGAZINE. NEW ©SERIES 7 DECADE ‘Ill. VOEIIN. No. IV.—APRIL, 1888. Ore GIN PAS, Avestan ees Ss Lato T.—On Some ScanpDInaviAN Puoybiocaripa. By Prof. T. Ruperr Jonus, F.R.S., and Dr. Henry Woopwarp, F.R.S. (PLATE VI.) (Continued from page 100.) 7. Tae Gastric Trera or Ceratiocaris. Pl. VI. Figs. 8, 9, 10; and Woodcuts, Figs. 1-9. N the Groroercan Magazine, Vol. II. 1865, p. 401, some account was given of the curious gastric teeth of Ceratiocaris and Dithyrocaris, from the Upper-Ludlow and Carboniferous strata of Scotland and Ireland; and in the Article Crustacna, by the same author, in the “ Encyclopedia Britannica,” vol. vi. 1877, p. 639, fig. 13, the relationship of such internal masticatory organs to the stomach of the Crab and Lobster, in particular, was treated in detail. Bohemian specimens.—The late M. Barrande, in his ‘Syst. Silur. Bohéme,” vol. i. Supplm. 1872, p. 448, plates 18, 21, and 31, described and figured several gastric teeth, presumably of more than one species of Ceratiocaris, which he had obtained from his ‘Stage H-e 2,” equivalent to the lower divisions of Murchison’s ‘‘ Upper Silurian.” These little fossils were found in the same beds with Ceratiocarides,' but could not with certainty be referred to their species. He described them as having a general resemblance among themselves, being somewhat crescent-shaped, slightly concave on one side and convex on the other, with the middle part thicker than the ends. He does not appear to have met with any having a basal, root-like or fang- like portion attached. The number of cusps observed by M. Barrande nearly always amounted to six, the exceptions being perhaps due (he thought) to the age of individuals. In some of the forms from Bohemia each cusp (seen from above) has the shape of a chevron, more or less distinct according to its place in the series; the strongest being in the middle, and the weakest towards the ends. Each chevron is hollow and sloping, with sharp borders. Thus, seen from above, the surface has a sharp, flexuous or zigzag ridge ; each bend forming a chevron and cusp. When perfect, there is a sharp point at the top of the chevron of each cusp, and often a smaller tubercle at each of its lower ends. In his pl. 21, figs. 41, 42, and 43, the chevrons of this zigzag ridge usually open 1 The species of Phyllocarida found in this Stage were Ceratiocaris Bohemica, C. docens, C. inequalis, with Aristozoé inclyta and A. Jonesi. DECADE III.—VOL. V.—NO. IV. 10 146 Prof. T. R. Jones and Dr. H. Woodward— towards the concave side, and their summits are towards the convex side. In fig. 44, and in others not figured, the reverse occurs ; and M. Barrande could not say if the difference were of generic or only of specific value. Possibly the difference may have been due to the right or left position of the “tooth ” when in place. Fig. 41 (9 mm. long) was found in the same strata with C. inequalis, Barr. Vig. 42 is 8 mm. long (Woodcut, Fig. 2), and fig. 43 is imperfect ; these were found in the strata with C. Bohemica, Barr. Vig. 44 (not quite perfect) is 14mm. long. In pl. 18, fig. 2 (15 mm. long) differs somewhat from the others; it looks more complicated, but has been perhaps decomposed into vertical parallel layers, concentric with the chevrons. The specimen in figs. 3 and 4 (30 mm. long) is obscure. Fig. 5 (24 mm.) shows four large cusps on one (concave ?) side; and six on the other, smaller, and perhaps representing the opposite ends of the chevrons. In pl. 31, fig. 21 (22 mm.) shows what appear like two nearly perfect rows of blunt cusps. Scandinavian specimens.—The “teeth” from Faro, Gothland, represented in our Pl. VI. Figs. 9 and 10, and Woodcuts, Figs. 1, 3, 4, belong apparently to two kinds. Figs. 10 a, b, ¢, are evidently related to those with cusps of a chevron-shape when looked at from above, and already referred to as described in M. Barrande’s “ Syst. Sil. Bohéme.” The chevrons, however, are less sharply angular in the flexuous ridges of the northern specimens (Fig. 10 c), and the cusps are not only less regular, but are much larger, higher, and sharper at one end of the tooth than the other (Figs. 10 a, 6, c). Fig. 8 (15 mm. long) shows five cusps of nearly equal size; and seen from above they appear to be united by a sharply-angular and regular zigzag ridge (Woodcuts, Figs. la, 1b), as in Barrande’s figs. 41, 42 (Woodcut, Fig. 2), and 44. His figures unfortunately do not give the side view for comparison,—only an imperfect vertical section, fig. 43. 3a ba Ne) 2 co, Fig. la. Side view of a ‘“‘tooth”; the same as Pl. VI. Fig. 8. From Faro. Nat. size. 1%. The same, seen from the top edge. », 2. A somewhat similar ‘tooth,’”? seen from the top. Barrande’s pl. 21, fig. 42 a, p. 443. From the Stage E of Bohemia. Nat. size. a. Side view of a‘ tooth.”? From Faro. Nat. size. 6. The other side of the same. a b {\ HS S i Side view of a “tooth.” From Faré. Nat. size. The other side of the same. Pl. VI. Fig. 9 a, b (14 mm. long) presents another shape altogether, inasmuch as the cusps keep nearly all in a single row without the Scandinavian Phyllocarida. 147 flexuous or zigzag ridge. They are six in number, blunt, and differ- ing much in size one from another; the middle of the body of the “tooth” is thicker than the ends. Two other specimens from the same locality have the cusps more distinctly arranged in two rows and somewhat alternating (Wood- cuts, Figs. 3 and 4). These in some respects approach fig. 21 in Barrande’s pl. 31. One of them is 17 mm., and the other (im- perfect ?) 10 mm. All the Scandinavian specimens of Crustacean teeth here men- tioned are from the Upper Silurian of the Isle of Faré, off the North-eastern extremity of Gothland. British specimens. —Fossil carapace-valves having irregular marks due to the presence of “teeth” within the squeezed valves of the carapace are not unusual in the collections from Lanarkshire. In the British Museum, “ No. 58878.” from Linburn, near Muirkirk, Lanarkshire, is a specimen showing a pair of “teeth,” each 8 mm. long, with six cusps, longer at one end of the “tooth” than the other (Woodeut, Fig. 7). Also another, “No. 45160,” figured in the Grou. Mac. 1865, PL XI. Fig. 2, from Lesmahago (Woodcut, Fig. 5). This measures 9 mm. long, and has an oblique basal portion, 10 mm. long. In the University Museum at Cambridge are two specimens. One of them, “0/11,” imperfect, with only four, rather long and irregular cusps (Woodcut, Fig. 7), is from Beck Mills, near Kendal (Upper-Ludlow Beds), and measures 6 mm. in length; and the other, ‘b/136,” from Lesmahago, Lanarkshire, has seven cusps, and is 12 mm. long, with an oblique root 15 mm. long ; the cusps are high and sharp at one end, and small and blunt at the other (Woodcut, Fig. 6). Referring to Gor. Mac. 1865, we see in Pl. XI. Fig. 1 (Ceratiocaris papilio, also from Lesmahago) that the ‘‘teeth” are made to appear as being opposed one to the other vertically (Woodeut, Fig. 9); this is, without doubt, due to the compression of the carapace, and to their being squeezed against the inside of the valves. In their normal position they would be opposed to each other horizontally, or nearly so. As regards the shape of these “teeth,” they resemble that of the others in the British Museum and those in the Cambridge Museum. In the Glasgow University Museum a fine example of C. stygia has similar teeth, also placed within the anterior portion of the carapace. All of these, however, have their cusps smaller and more regular than those in our Pl. VI. Fig. 10; they do not quite agree with our Fig. 8, which is probably allied to Barrande’s pl. 21, figs. 41-44 (judging chiefly from the upper surface); and they differ much from our Pl. VI. Fig. 9. The specimens in the British Museum (Nos. 45160 and 58878), and the more perfect specimen of the two in the Cambridge Museum, differ materially from the Bohemian and Scandinavian specimens in the more trenchant character of their cutting edges, and in the broad elongated bases of attachment, suggesting that we may be here 5 dealing with two forms of masticatory organs,—namely, (1) a thicker 148 Prof. T. R. Jones and Dr. H. Woodward— and more solid form, being probably true gastric teeth; and (2) a compressed trenchant type, being a portion of the true mandible. Some, indeed, of the European forms also may have belonged to this latter type; but, as the bases (if ever existent) have been broken off in the Gothland examples, and hidden in the figures of those from Bohemia, we are unable to speak with confidence as to this part of their structure. The differences, moreover, in the material in which they have been imbedded, and in the conditions of pressure and fossilization, may have modified the organisms to a very consider- able degree. oa zy) Specimen ‘45160’ in British Museum. From Lesmahago. Nat. size. Specimen ‘“ 4/136”’ in Cambridge Museum. From Lesmahago, Nat. size. Specimen “58878”’ in British Museum. From Lesmahago. Nat. size. Specimen ‘‘6/11” in Cambridge Mus. From Beck Mills, Kendal. Nat. size. Part of specimen “ 47989’ in the British Museum, showing the position of the ‘‘ teeth” in the anterior region of the carapace of Ceratiocaris papilio. From Lesmahago, Lanarkshire. Nat. size. We cannot pretend to refer these fossil teeth to the known species of Ceratiocaris ; but evidently there are six different forms ; thus :— 1. With neatly chevron-shaped cusps, regular in size. Woodcut, Fig. 2, Barrande’s pl. 18,2: 2 (2); pl. 21,1. 41-44; and Pl. VI. Fig. 8. 2. Small neat cusps, longer at one end of the tooth than at the other. Woodcuts, Figs. 5, 6, 7, 8 (£), 9. 3. Cusps with a more flexuous connecting ridge. Pl. VI. Figs. 10 a, 10 3, 10 ¢. 4. OCusps in two parallel rows, but somewhat alternate. Barrande’s pl. 31, f. 21. 5. Cusps irregularly alternate in two rows. Woodcuts, Figs. 3 and 4. 6. Cusps ina single row. Pl. VI. Figs. 9 a, 9 0. Note.—It may be well to mention that in the “‘ Quart. Journ. Geol. Soe.” vol. xvii. 1861, pp. 542-652, pl. 17, Dr. J. Harley described and figured numerous small, waterworn, organic fragments from the Ludlow Bone-bed, under the generic name of Astacoderma; and he referred them to a Crustacean origin, mostly as being morsels of the harder parts of tests and limbs, but in two instances as having some resemblance to ‘‘ the stomach-teeth of the common Lobster ” (p. 550, pl. 17, figs. 11-18). In “Siluria,” 8rd (called the “ 4th”) edit. 1867, p. 542, it was suggested that all the specimens figured by Dr. Harley, excepting figs. 15 and 16, were really portions of the teeth of Phyllopod Crustaceans such as Ceratiocaris. Scandinavian Phyllocarida. 149 II. Poaseanocaris, Novak. Sitzungsb. k. béhm. Gesell. Wissensch. 1886, p. 1, pl. i. 1. Paascanocaris pucio (Hurypterus, Barrande'), Novak. Loc. cit. 1**, PHasGANOcARIS PuGIO (Barrande), var. SERRATA, J. & W. Plate VI. Figs. 3-7. Fifth Report on the Paleozoic Phyllopoda, 1887, p. 3; Report Brit. Assoc. for 1887 (1888), p. 62. Four flattened pieces (Figs. 3-6) of tapering, riband-like telsons, with a central line, sometimes raised, but usually sunken, which was originally a ridge in all probability. From it, on each side, numerous parallel, oblique, sigmoid lines pass downwards and outwards, and these end at the edges with sharp upward curves, defining the small sub-triangular teeth of a serrated fringe. This is of varying strength, and is sometimes backed by a slight ridge. Except in the serrated edges these specimens correspond in essential particulars with the dorsal aspect of the triangular or bayonet-like lower portion of the telsons referred by Barrande to Eurypterus, but by O. Novak, lately and with precision, to his new genus Phasganocaris. These fragments, dark brown and chitinous in appearance, are in an earthy yellowish-grey limestone (Lower Ludlow) from Vatten- fallet (the Waterfall) near Wisby, Gothland. Fig. 7 shows a longer and narrower piece of a telson, badly pre- served, much crushed and wrinkled, but retaining some convexity, and its upper end showing a slightly triangular section. It is dark- brown and chitinous, in a blue-grey, calcareous, and finely micaceous shale (of the Ludlow series), from the Ringsjén, Scania. EXPLANATION OF PLATE VI. Fic. 1. Ceratiocaris Scharyi, Barrande. 1 a, abdominal segments; nat. size. 1b, one of the segments and part of another, magnified 3 diam. The Ringsj6n, Scania. » 2. ©. pectinata, J. & W. 2a, ultimate segment, telson (style), and one stylet ; nat. size. 246, a portion of the segments, magnified 4 diam. The Ringsjon. », 8, 4,5. Phasganocaris pugio (Barr.), var. serrata, J. & W. Portions of telsons, magnified 2 diam., and Fig. 6, nat. size. From Vattenfallet, Wisby, Gothland. », 7. P. pugio, var. serrata, J. & W., nat. size. From the Ringsjén, Scania. Tooth of Ceratiocaris ; side view; nat. size. Tooth of Ceratiocaris. 9a, side view; nat. size. 9 6, top view; magn. 2 diam. », 10. Tooth of Ceratiocaris. 10a and 10 3, side views; nat. size. 10 ¢, top view. Magn. 2 diam. Figs. 8-10 are from the Isle of Faré, north of Gothland. Wolo on f Supplemental Note on Ceratrocaris ANGELINI. Pl. V. Fig. 1. Prof. Lindstrém has favoured us with a careful sketch of the ridges and pits seen on the original specimen of Ceratiocaris Angelini, J. & W., but very obscure on the plaster cast. He writes (Mar. 2) : “The tip of the telson in Cer. Angelini is only slightly longer than 1 E, pugio, Barr. Sil. Syst. Bohéme, vol. i. Suppl. p. 564, pl. xxvi. figs. 25-34, and pl, xxxiy. figs. 7-9. 150 Prof. H. A. Nicholson—Structure of Cleistopora. that of the plaster cast. Its total length is 148 mm., and there is thus a difference of only 7 mm: between the original and your figure. I enclose a fairly good sketch of the row of impressions on the left side of the telson as seen in the original. They are visible for a length of 57 millim. from the broken tip upwards and are very small, about 14 being contained within a length of five milli- métres.” Fic. 10. A small portion of the original specimen of the telson of Ceratiocaris Angelini, from the left-hand side, as figured in Plate V. Fig. 1. Magnified 4 diameters. I].—On vue Srrucrure or Czzisrorora (Micu@1inia) GEOMETRICA, Edwards & Haime, sp. By H. Aturyne Nicnotson, M.D., D.Sc, F.G.S., Regius Professor of Natural History in the University of Aberdeen. {* their great work upon the Paleozoic Corals (Polypiers Foss. des Terr. Pal. p. 252, pl. 17, figs. 3, 8a, 1851) Milne Edwards and Haime describe and figure, under the name of Michelinia yeometrica, a remarkable little Coral from the Devonian rocks of France. By the kindness of Dr. Daniel Gihlert, of Laval, whose researches upon the stratigraphy and paleontology of the French Devonian rocks are well known, I have been enabled to examine some well-preserved examples of this interesting form, and have determined some new facts as to its internal structure. Investigation by means of thin sections has, in fact, shown that this Coral has in reality no close relationships with the genus Michelinia, but that its affinities are rather with Protarea, EK. & H. It differs, however, in important ~~structural features from Protar@a, and appears to form the type of a ( new genus to which the name Cleistopora may be given. Cleistopora geometrica, K-and H. sp. (Fig. 1, A), is a little discoid Coral, averaging from one and a half to two centimétres in diameter, from two to three millimétres in thickness in the middle, and usually attached parasitically to a Brachiopod or other foreign body. In some cases it appears to have been free. The short vertical corallites terminate in shallow hexagonal calices, which are mostly from five to six millimétres in diameter. The floor of each calice is formed by a flat or slightly convex surface, more or less clearly reticulated, which was regarded by Milne Edwards and Haime as being constituted by the highest of the ‘“tabule,” which they sup- posed to possess a strongly granulated exterior. Examination by means of thin sections (Fig. 1, C) shows, however, that “tabule ” are entirely wanting, and that the whole visceral chamber, below the level of the calice, is occupied by a mass of reticulate or tra- becular tissue, formed by irregularly anastomosing calcareous fibres. Prof. H. A. Nicholson—Structure of Cleistopora. 151 This characteristic structure is shown equally well both by vertical and tangential sections (Fig. 1, C and D). The walls of the corallites are thick, and when viewed in section under the microscope exhibit tolerably well the peculiar fibrous and subcrystalline structure which is seen in sections of many recent Corals. A true “primordial wall,” such as is seen in many species of Favosites, does not seem to be present; but the junction between adjacent corallites is usually marked by an irregular dark line. The visceral cavities of contiguous tubes are placed in communication by irregular canals, which represent the “mural pores” of the Favositide. Septa are only represented feebly, by a number of obscure ridges or striz. & Fie. 1. Cleistopora geometrica, Edw. & Haime, sp. A. Upper surface of a full- sized individual, of the natural size. B. A single calice enlarged. C. Vertical section of a specimen growing upon a Brachiopod, enlarged five times. LD. Tangential section of the same specimen similarly enlarged. From the above description it will be evident that Cleistopora geometrica KH. & H.sp.,is a Perforate Madreporarian, and that it is related to Protarea, EK. & H. In this latter genus, however, the visceral chambers of the corallites are very short, and are not filled up in their basal portion with the reticulated endothecal tissue, which is characteristic of the genus Clezstopora. From the genus Michelinia, De Kon., Cleistopora is sufficiently separated, not only by the possession of the peculiar trabecular infilling of the lower part of the visceral chambers, but also by the total absence of tabula, while the “mural pores” are only repre- sented by vermicular and tortuous tubes passing through the walls of the corallites. In the general aspect of the corallum, Cleistopora geometrica presents a considerable resemblance to the species of Pleurodictyum, Golf., from which, however, it is separated by characters similar to those which distinguish it from Michelinia. 152 Prof. von Ettingshausen—Ceratozamia in Styria. Another distinctive character in Pleurodictywm—which I have recently determined by an examination of well-preserved specimens from the Corniferous Limestone of North America—is that in this genus the basal epithecal plate is pierced by numerous well-marked foramina, formed by the external openings of the mural pores of the marginal corallites. It is probable that this character will be found to be constant in the genus Pleurodictyum, but I am not at present in a position to affirm that it is so. The genus Cleistopora, Nich., may be defined as follows :— Corallum small, discoid, usually attached by its entire base to foreign bodies. Corallites short, prismatic, without tabule, and having the inferior portion of the visceral chamber completely filled up with loosely reticulate calcareous tissue. Septa represented by strie only. Walls thick, traversed by minute irregular canals or pores. The specimens of Cleistopora geometrica, EK. & H. sp., which I have examined, were collected by be Daniel Gihlert in the Devonian rocks of Viré, France. IJJ.—Own THe Occurrence oF A CERATOZAMIA IN THE TERTIARY Fiora or Lrospen 1N STYRIA. By Dr. Constantin Baron yon Errinesuausen, F.C.G.S., Professor of Botany, University of Graz, Austria. 7% ADOLPH HOFFMANN has kindly sent me a large series of fossil plants from the Tertiary strata of Leoben containing a very rich fossil flora. On examining the latter, I discovered a fossil leaf, which I at once recognized as a Cycad. Remains of that family of plants are extraordinarily rare in the Tertiary strata of Europe. They are limited almost entirely to the Eocene formation. The occurrence, therefore, of such a fossil in the Tertiary flora of Leoben, which belongs to the Miocene period, calls forth the greatest interest, and I shall not fail to give a preliminary notice on the subject to paleontologists. The leaf-fossil resembles very much the leaf of Ceratozamia, a Mexican genus. It shows lanceolate-linear segments which are narrowed towards both ends and somewhat falciform. The borders are not toothed. The segments are 17 centimetres long and 174 milli- métres broad. The texture is firm, coriaceous. The nervation con- sists of 16 longitudinal nerves, being equally thin and undivided. They are rather prominent. The epidermis is well preserved and shows stomata which, relating to form and position, agree very closely with those of Ceratozamia. Though I do not doubt that the fossil here described is a Oycad, it is well to take into consideration other possible determinations. In the first place there are the Coniferee to be named to which the above fossil may be referred, especially the genus Dammara. But the leaves of the Dammara-species are simple, not divided, and relatively broader than the segments of the fossil in question, though structure and nervation do not differ in either. On account of the R. NM. Deeley—Glacial Deposits in the Midlands, ete. 158 longitudinal nerves being prominent, one might even be tempted, in determining this fossil, to consider the Graminee also. But the firm texture and the quality of the epidermis of the leaf do not admit of such a view. I have named the species Ceratozamia Hoffmanni. The fossil leaf above described will be figured in my Memoir on the Tertiary Flora of Leoben. TV.—Correnation oF tHE LinconnsHirE PuerstoceNe Deposits * WITH THOSE oF THE Mip1LAND CouNTIES. By R. M. Drsxey, Esq. HE Memoir of the Geological Survey on ‘“‘ The Geology of Part of Hast Lincolnshire,” by A. J. Jukes-Browne, lately reviewed in the Grotoetcat Magazine, proves so interesting that I am tempted to compare the classification of the Glacial deposits which he has adopted with that I have proposed for the Midland Counties. There are also some features in the distribution and lithological characters of the Boulder Clays to which I should like to draw attention. At the outset Mr. Jukes-Browne shows that there are in Lincoln- shire two types of Boulder Clay occupying areas separated from each other by the Chalk Wolds. These two deposits, which he regards as having been formed at different stages of the Pleistocene period, are described as the “Older” and the “‘ Newer Boulder Clay.” The Older Boulder Clay, the Chalky Boulder Clay of Mr. Searles Wood, an intensely chalky deposit, is only found on the west side of Sheet 84 of the Ordnance Survey. The Newer deposits are brown or purple clays, which rise up from beneath the alluvium stretching along the coast. Both these deposits contain intercalated beds of sand or gravel. In a paper printed in the Quart. Journ. Geological Soc. vol. xli. p. 114, Mr. Jukes-Browne shows that the brown or purple clays, generally known as the Hessle and Purple Clays, frequently occupy interglacial valleys cut through the older Chalky Boulder Clay. In my own paper I found it most convenient to divide the Pleistocene period into three epochs, namely, Older, Middle, and Newer Pleistocene, the Great Chalky Boulder Clay and associated chalky gravels being relegated to the Middle Pleisto- cene division, an arrangement which might also be adopted for the similar deposits of Lincolnshire. As far as I am aware the only Older Pleistocene deposit in this county is the mass of Quartzose Sand on the hill near Gelston, north of Grantham. A careful search would doubtless reveal many other sections both of Boulder Clay and gravel. Too much reliance must not be placed on the colour of a deposit. Similarity of colour no doubt indicates that the materials forming the different deposits have been derived from similar rocks, but we must not be too ready to assume that it also indicates similarity of age. In the Midland Counties the adoption of such a test would lead to great confusion, for in this area the Older and Newer Pleistocene clays, having been generally formed by the breaking up of similar rocks, are somewhat similar in colour, 154 R. WM. Deeley—Glacial Deposits in the Midlands, ete. and yet they are separated from each other by the whole of the Middle Pleistocene series. I do not mean to affirm that on this account the classification adopted by Mr. Jukes-Browne is incorrect, but it is possible that some of the brown and purple clays he describes belong to the Older and not to the Newer Pleistocene series. Such deposits would be difficult to recognize on the east side of the Chalk Wolds, as they would contain chalk and flint; but on the west the comparative scarcity or even total absence of these rocks should render their detection tolerably easy. In the Trent Basin, south and west of Newark, there are no signs of a submergence having occurred in Newer Pleistocene times. With the close of the Middle Pleistocene epoch marine conditions came to an end, and rivers commenced to re-excavate their valleys through the masses of Boulder Clay and .sand which had been formed in them. Subaerial erosion also seems to have been active in Lincolnshire at the same time, for there the Newer Pleistocene Hessle and Purple Boulder Clays are found at low levels in valleys excavated subsequently to the formation of the Chalky Boulder Clay. This would make the Later Pennine Boulder Clay of the Midland Counties the equivalent of the Hessle and Purple Clays. In the Trent Basin, as I have remarked, the Later Pennine Boulder Clay shows no signs of aqueous action, whereas the equivalent low-level deposits in Lincolnshire seem to be of marine origin. If we admit the possibility of a Newer Pleisto- cene submergence of about 400 feet, such as Mr. Jukes-Browne requires, great difficulties present themselves; indeed, it would be necessary to assume great but local earth-movements without we imagine the whole of Central England to have been occupied by an ice-sheet, which displaced the water. The severity of the glacial conditions which really obtained in Newer Pleistocene times is as yet scarcely realized, yet at this age the cold was sufficiently severe to permanently freeze the ground in the South of England, and bring down great glaciers from the Cambrian and Cumbrian Moun- tains, which, spreading over Lancashire and Cheshire, eventually passed over the watershed into the Trent Basin. I am aware that this is disputed, many geologists regarding the striz as being due to large icebergs grating along the bottom of a sea about 1200 feet deep; glaciers being with them ata discount. Now an iceberg is merely a fragment of a glacier, and therefore the larger the iceberg the larger the glacier. Consequently I prefer to make my glaciers larger than my icebergs, not vice versa. During the Middle Pleistocene epoch the ice-flow seems to have passed from the north-east over the submerged Chalk Wolds, giving rise to the intensely Chalky Boulder-clay. Ata still later stage, in Newer Pleistocene times, the ice came from the Pennine Hills or further west, and passing down the Trent Valley, pressed against the escarpment of the Middle Oolite. Through the gaps of the Humber and Witham Valleys the subglacial streams poured their sediment into the sea forming the Purple Clays. At one time it is probable that the ice actually passed out through the Witham and J. A. Symonds—Avalanches and Avalanche Blasts. 159 Humber Valleys, or even over the Wolds as well, giving rise to the more chalky Hessle Clay. Before accepting a submergence of 400 feet, very strong proofs will have to be furnished, not only of the marine aspect of the high-level brown Boulder Clays, but also of their Newer Pleistocene age. V.—AVALANCHES AND AVALANCHE Buasts.—-“‘ WINTER IN THE Hieu Apes.” By Jonun AppincTon Symonps, Esq. ie following important and interesting notes on avalanches and the dangerous wind-blasts they cause, appeared in the Pali Mall Gazette for February 28th, 1888. As we do not remember to have seen the geological effects of these phenomena described in any detail in our numerous geological text-books, we believe Mr. Symonds’ notes on the subject will be of much interest to readers of the GrotocicaL MaGaziIne. “« Feb. 6.—We reckoned another foot of snow this morning. The Fluela Pass, which connects us with the Lower Engadine, was closed to traffic. Just before noon a man called Anton Broher, known among his comrades as “the Knave of Spades,” because he had a bushy black beard, was swept away by an avalanche below Tschuggen, on the Fluela road, about three miles from Davos Platz. Hye-witnesses saw him carried by the blast of the avalanche, together with his horse and sledge, three hundred yards in the air across the mountain stream. The snow which followed buried him. He was subsequently dug out dead, with his horse dead, and the sledge beside him. The harness had been blown to ribbons in the air; for nothing could be found of it, except the head-piece on the horse’s neck. This violence of the wind which precedes an avalanche is well authenticated. A carter, whom I know, once told me that he was driving his sledge with two horses on the Albula Pass, when an avalanche fell upon the opposite side of the gorge. It did not catch him. But the blast carried him and his horses and the sledge at one swoop over into deep snow, whence they emerged with difficulty. Another man, who is well known to me, showed me a spot in the Schaufigg Valley (between Chur and the Streda Pass) where one of his female relatives had been caught by the wind of an avalanche. She was walking to church when this happened. The blast lifted her into the air, swept her from the road, and landed her at the top of a lofty pine, to which she clung with all the energy of desperation, The snow rushed under her, and left the pine standing. It must have been a trifling avalanche. Her friends, returning from church, saw her clutching for bare life upon the tree, and rescued her. Many such cases could be mentioned. A road-maker named Schorta this winter was blown in like manner into the air below Zernetz, and saved himself by grappling to a fir tree. J have been shown a place near Ems, in the Rhine Valley, not far from Chur, where a miller’s house was carried some distance through the air by an 156 =J. A. Symonds—Avalanches and Avalanche Blasts. avalanche blast. Its inhabitants were all killed, except an old man above sixty and a child of two years. Again, I may mention that the tower of the monastery at Dissentis was on one occasion blown down by the same cause. In order to understand the force of the ‘* Lavinen-Dunst,” as this blast is called here, we must remember that hundreds of thousands of tons of snow are suddenly set in motion in narrow chasms. The air displaced before them acts upon objects in their way like breath blown into a pea-shooter. feb. 7.—It is still snowing. We reckon that there is an average depth of five feet in the valley. In the woods, and where it has drifted, the snow is of course much deeper. Four large avalanches fell to-day between Frauenkirch and Schmelzboden. One of them, in the Rutsch-tobel, below Monstein, caught some men working on the road. The man in advance, Caspar Valir, was blown across the stream and buried. The others managed to extricate themselves. I have since then seen this avalanche. It covers about five acres in the valley, and has a depth in the deepest place of at least sixty feet. The trees on a hill above it have been mown down by the violence of the wind it carried [sucked after it ? ]. Feb. 9.—It is still snowing. The road between Davos and Wiesen is said to be impassable. The electric light is extinct in Davos Platz to-night, owing to an immense avalanche, which fell in the Dischma Thal and choked the water supply, I must observe that when there is a considerable frost, the snow does not get easily into motion, and so there is less risk of avalanches. The greatest danger is when a thaw, with blustering warm wind, sets in while the snow is still falling. There are, roughly speaking, three sorts of avalanches. One is called “Staub Lavine,” and descends when the snow is loose and recently fallen. It is attended with a whirlwind, which lifts the snow of a whole mountain side into the air and drives it onwards. It advances in a straight line, overwhelming every obstacle, and is by far the most formidable of the three sorts. The second is called “Grund Lavine.” It falls generally in the spring-time, when the firm winter snow has been loosened by warm thawing breezes. The snow is not whirled into the air, but slips along the ground in enormous masses, gathering volume and momentum as it goes, and finding a way forward by its own weight. The third is called “Schnee-Rutsch,” or snow-slip. It consists of a portion of snow detached upon a mountain slope, down which it slides gently, heaping itself gradually higher till it comes to rest on a level space. Small as the slip may be, it is very dangerous. The snow in motion catches the legs of a man, carries him off his feet, creeps up to his chest, and binds his arms to his side, being compressed by motion into a firm substance like hardening plaster of Paris. I once saw a coal cart with two horses and a man swept away by a very trifling slip of this sort. The man and one horse managed to keep their heads above it and were rescued. ‘The other horse was stifled before he could be dug out. Feb. 12.—Drove over the avalanches to Wiesen. At Glarus saw fifty-two men digging for the body of Caspar Valir. They have Notices of Memoirs—Prof. Dames on Titanichthys pharao. 157 been digging since the 7th, but in vain. His corpse will not be found until the spring. Meanwhile his widow is lying in a house which overlooks the place where her husband was overwhelmed. Avalanches have descended on both sides of the hill on which this homestead stands. The gorge which separates Davos from Wiesen, called the “ Ziige,” or the “‘ Paths of Avalanches,” is a mere wilder- ness of snow shot down from either side.” That the weather this winter on the Continent has been exception- ally severe is still further shown by the following extracts from long and numerous newspaper reports :— “ Heavy snowfalls were again reported yesterday from the central districts of Northern Italy, where it is stated that in some places the snow is as much as ten feet deep. The Alpine troops with the Carabineers, under the direction and leadership of the authorities, have been working heroically in the task of rescuing the people of the small villages which have been buried in the masses of snow. By the latest accounts more than 200 bodies had been taken out. The hamlet of Trasquera, in Piedmont, at the foot of the Simplon, has been completely overwhelmed by an avalanche. In the Bini valley five persons have been killed by an avalanche. “The strange coincidence of a violent thunderstorm and a heavy fall of snow occurring at the same time took place on Saturday morning in the Giant Mountains near Gorlitz, in Silesia. “Two avalanches have fallen on the famous hospice of St. Bernard. The church has been almost entirely buried in snow.” (Communicated by C. Davies Sherborn, F.G.S.) Ni @ eh sEy SS) Orn Vile VE@ TES: 2. I.—Titanichthys pharao, nov. gen. et nov. sp., AUS DER KREIDEFOR- MATION ArGyprEeNS. By Prof. Dr. W. Dames. Sitzungsb. Ges. naturf. Freunde Berlin, 1887, pp. 69-72, woodcuts. OME detached and partially broken teeth from the Lower Seno- bh) nian of Hgypt are described by Dr. Dames under the name of Titanichthys pharao. The specimens were obtained by Dr. Schwein- furth about 10 kilometres west of the Pyramids of Gizeh, and, when complete, measure 60 millim. in length. They are laterally-com- pressed teeth, with a very long root, rapidly tapering upwards, and marked by deep longitudinal furrows. The enamelled crown is relatively small, and of an unsymmetrical arrow-head shape, over- hanging the summit of the root in front and behind, and thus giving the tooth a barbed character. The genus thus imperfectly indicated is regarded as new, and placed (with Hnchodus) in the Trichiuride ; if really undescribed, however, it will require another name, Titan- ichthys having been preoccupied by Newberry for a huge Placoderm (Trans. New York Acad. 1885). 158 Reviews—Prof. Prestwich’s Geology, Vol. II. Il.—Diz Garrune Saurodon, Hays. By Prof. Dr. W. Dames. Ibid. pp. T2—78. URING the investigation of the teeth of Titanichthys, Dr. Dames D was led to study the semi-barbed teeth from the Huropean Chalk originally referred by Agassiz to the American genus and species Saurodon Leanus, Hays. The result is an interesting resumé of the varied fate of the fossils in question at the hands of different palee- ontologists. Their resemblance to the teeth of the Trichiuride is dis- cussed, and full references are given to the several descriptions and fizures. It is unfortunate, however, that Hays’ original memoir has not been consulted, nor yet the most important contributions of Leidy (Trans. Amer. Phil. Soc. vol. xi.) and E. T. Newton (Quart. Journ. Geol. Soc. vol. xxxiv.). The latter authors have shown that the European fossils are certainly not referable to Saurocephalus (of which Saurodon is a synonym), and those from the English Chalk are named Cimolichthys levesiensis. A. 8. W. aS a We IG eH Wass I.—Geronocy, Curmican, PuysicaL, AND STRATIGRAPHICAL. By JosepH Prestwicu, M.A., F.R.S., F.G.8. In T’'wo Volumes. Vol. I]. SrratiGRaPHicaL AND PuysicaL. Royal 8vo. pp. xxviii. and 606, with Geological Map of Europe, and numerous I1lustra- tions. (Oxford, at the Clarendon Press, 1888.) F the number of geological papers published every year in various parts of the globe were taken as a measure of the increase of our knowledge, our sentiments on the subject might fitly find utterance in the word “ Prodigious!” Nevertheless, while this great “talus heap of geological literature,” as it has been rather irreverently termed, may at times produce a feeling of dismay and oppression, yet we may derive comfort from the thought that in due course of time the leading facts and the general results of this mass of information are tabulated and expounded in the larger Text-Books and Manuals. Our advances in geological knowledge are then best gauged by such works as the one now before us, written as it is by one of our geological leaders, and whose object it is to exhibit the present state of the science. It might indeed be maintained that we are already well supplied with Manuals of Geology—Physical, Stratigraphical, and Paleontological; but it may also fairly be urged that one individual might devote his whole time to the literature past and present, and never learn a tithe of all that has been done in geology. Consequently the deficiencies of one work are compensated by others: and while we give honoured places on our bookshelves to the general Manuals of the older geologists—to Buckland, Bakewell, Trimmer, De la Beche, Phillips, Lyell, and Jukes, the value of whose works is now to a large extent historical; so alongside of Geikie, Green, Seeley, and Etheridge, we accord a hearty welcome to the two hand- some volumes by the ex-Professor of Geology at Oxford. Reviews—Prof. Prestwich’s Geology, Vol. IT. 159 Two years have elapsed since the publication of the first volume of Prof. Prestwich’s work (see notice in Grou. Maa. for 1886, p. 81), but the delay is amply explained by the amount of labour involved in the preparation of this second and larger volume—indeed the illustrations alone must have cost the author a very great deal of thought and attention. With regard to the aspect of the volume itself, we can only repeat what was said before, and speak in the highest terms of the clearness of the type, the excellence of the paper, and the beauty of the woodcuts and lithographic plates. In the matter of illustrations this second volume is even more profusely adorned than its predecessor. ‘The large map of Hurope, printed in colours and mounted on linen, which acts as a folding frontispiece, will in itself be a treasure to geologists. It is the work of Mr. W. Topley and Mr. J. G. Goodchild, and shows very clearly the distri- bution of the principal geological formations. Besides 256 woodcuts, a large number of which have been expressly engraved for this work, there are 16 lithographic plates showing characteristic fossils of different formations ; they have been drawn on stone by Miss Ger- trude Woodward, and we may observe that we have seldom seen in any geological work illustrations which for beauty and accuracy are equal to these. The woodcuts include pictorial views of scenery as well as groups of fossils, and sections to show the structure of various districts; and there is also a map showing the probable extent of land covered by ice and snow during the Glacial Period. It is no exaggeration then to state that this is the best printed and best illus- trated geological text-book that has been produced in this country. The former volume dealt with rocks, sedimentary and eruptive, and their method of formation ; it treated of ice and ice-action, coral- islands, earthquakes and volcanoes, underground water and springs, metalliferous deposits, and metamorphism. The present work is mainly devoted to the geological history of the stratified rocks. Commencing with a brief account of the early conditions of the earth’s crust, the author gives a condensed account of the various formations in ascending order, pointing out their chief physical features, the forms of life represented at each great period, and the distribution of the rocks over the surface of the globe. In such a comprehensive survey it is impossible to enter into much detail respecting the minor divisions of the rocks, and their varying lithological characters, but strict impartiality so to speak in dealing with different formations is apt to detract from originality, and may well be pardoned. Nevertheless we feel that some forma- tions have received but scant courtesy, and this remark refers especially to the Devonian rocks and Old Red Sandstone, and to the Carboniferous Limestone Series. On the other hand, the Corallian rocks and some of the Tertiary strata are treated in considerable detail. But while the stratigraphical features of the rocks are for the most part dealt with in a broad and general way, their palon- tology is very fully discussed. The leading genera and many of the species are enumerated, while paleontological summaries are given of the life of the larger divisions of the strata, showing the 160 Reviews—Prof. Prestwich’s Geology, Vol. IT. period of incoming of the different classes, and the orders and genera peculiar to the Paleozoic, Mesozoic, and Kainozoic eras. In the various tables which he has prepared the author acknowledges his indebtedness to the elaborate work on Stratigraphical Geology and Paleontology issued in 1885 by Mr. Etheridge. Of great value to students will be the excellent accounts of the foreign equivalents of our strata, one of the most important features in this work. Not only are the sedimentary rocks in different parts of Europe described, together with their chief paleontological features, but the rocks so far as they have been determined in other parts of the globe are likewise mentioned: so that with the aid of the geological map of Europe prefixed to this volume, and the smaller geological map of the world prefixed to the former volume, the student can follow out the geographical distribution of the main divisions of the strata and make himself acquainted with the principal facts in their life-history. Several Tables of Strata are given in the volume before us. Table I. shows the Sedimentary Strata in England and their Correlation with some of the principal Continental Groups. Then follow Tables of the formations in India, North America, Australia, New Zealand, and South Africa ; these include lists of the characteristic fossil genera of the principal divisions, and a column showing the probable age of the formations compared with the general “ time-divisions”’ in Europe. It appears likely that the Table of English formations was printed off some time before the rest of the work was in type, for we notice several discrepancies between the grouping adopted in the table and that in the text. Thus in the former the Folkestone Beds are placed with the Gault, and in the latter they are grouped with the Lower Greensand. The Lenham Sands are doubtfully placed with the Miocene in the Table, and later on they are provisionally placed with the Pliocene; the Bure Valley Crag is classed as pre-Glacial in the Table, while in the text further on it is grouped with the Pliocene as part of the Norwich Crag. Moreover, in this Table the Recent deposits are not given so much prominence as they are in Table IJ., and curiously enough they are separated from the Quaternary Period. The term Kainozoic should be employed as a comprehensive term to embrace both Tertiary and Quaternary. The terms pre-Glacial and post-Glacial are still used by Prof. Prestwich, although vague terms of this character are much to be deprecated, as they are liable to be used in different senses by different writers, and they have thus no definite chronological value. Noteworthy instances of this have occurred at recent meetings of the Geological Society. The term Oligocene is adopted, the Permian is grouped with the Palzeozoic, while the Silurian is employed in the old Murchisonian sense, although the term Ordovician, now very largely used for the ‘“ Lower Silurian ” strata, is mentioned in a footnote. On the whole, however, we are glad to find that the old familiar names of formations are used by the author. If the labours of original workers are more or less hidden in Reviews—Prof. Prestwich’s Geology, Vol. I. 161 the “talus” before mentioned, so we naturally look for a due record and acknowledgment of them by those who have sifted out and sorted the facts; and the long list of authorities referred to or quoted by Prof. Prestwich will testify to his laborious research. Liven then we miss some well-known names, but when we remember that the “talus” includes 43 volumes of the Quarterly Journal, 24 Geological Magazines, 41 volumes of the Paleeontographical Society, not to mention countless other Journals, T'ransactions and Proceed- ings at home and abroad, some omissions are not surprising, for even the ‘“ Geological Record” has failed to keep pace with these publications... And among the long list of papers there are many whose interest is purely local, and others that tend but little to advance our general knowledge. It might be observed, however, that authors would facilitate the study of the literature were each one to add a summary of his views and conclusions at the end of his papers. Geology is indebted, however, not only to those who have written papers on various subjects: it is also largely indebted to many individuals who have never committed their views to print. This is particularly the case with our local geologists who have accumu- lated large collections of fossils, and who are ever ready to commu- nicate their knowledge to those who come in search of it. In reviewing the present work we naturally turn to portions which deal with debateable subjects, but as a rule we do not find special verdicts on vexed stratigraphical questions, even when we might expect them, the reader being left to form his own judgment; the most original portions of the book are those which deal with ques- tions in physical geology. In briefly treating of the Archean rocks, the author observes that “although great heat and pressure might effect radical changes in early sediments when covered up by thick masses of newer rocks,— as are the gneissic rocks of North-Western Scotland, or the felsitic rocks of Wales, by overlying Cambrian and Silurian strata,—they would not affect Archean areas such as those of North America and Scandinavia, which we have reason to suppose have never been covered, or only to a very slight extent, by newer strata, and which, nevertheless, exhibit either the effects of intense metamorphism, or else the effects of hydro-thermal conditions originally different.” These views will no doubt interest students of these ancient rocks ; we may also note that the organic nature of Hozoon is practically accepted by the author. In his account of the Cambrian and Silurian rocks some mention of Barrande’s ‘Colonies’ might have been given, and also of Mr. Marr’s modified interpretation of them. The author considers that, during the Coal-period, the atmosphere was more dense, and more charged with moisture and carbonic acid, and he is led ‘to conclude that the coal-growth was in all probability one of extreme rapidity, and consisted of woods and plants contain- 1 The Geological Record for 1879 was published in 1887. DECADE III.—VOL. V.—NO. IV. 11 162 Reriews—Prof. Prestwich’s Geology, Vol. II. ing a much larger proportion of carbon than any existing forest vegetation.” With regard to the excess of carbonic acid gas, Mr. Carruthers has expressed an adverse opinion, and experiments made on living plants have shown that they are liable to be poisoned, like animals, by an excess of the gas.! On the question of the duration of Coal, Prof. Prestwich adheres to the opinion expressed by the Royal Commission of 1871, that allowing for the rapidly increasing rate of consumption, the supply may last for about 400 years. It is interesting to learn that a coal- pit at Ashton Moss in the Manchester Coal-field has recently been sunk to the great depth of 2850 feet, and another pit in Belgium to o411 feet. In dealing with the Permian and Triassic rocks the author refers to the great earth-movements that took place before and between these periods, but it is not perhaps sufficiently pointed out that in this country the greatest physical break is at the base of the Permian. With regard to the Trias, the central division known on the Continent as the Muschelkalk ‘is wanting, unless it be represented by the ‘ Water-stones.’”’ Here some allusion might have been made to the sequence of Red Rocks in Devonshire, and to Mr. Ussher’s sub- divisions of Upper, Middle, and Lower Trias. The author devotes some space to the subjects of rock-salt and gypsum, and illustrates his remarks with an account of a boring in Haute-Sadne. The origin of the colour of the red rocks and the causes of the rarity of fossils are also discussed. The Rheetic Beds are grouped with the Trias, but the White Lias is divorced from them and placed with the “Infra-Lias.”’ This is not a happy arrangement, especially too when the White Lias and Sutton Stone are associated and their fossils intermingled. The latter deposit was grouped by Charles Moore in the Zone of Ammonites angulatus, and although this is a debateable subject, yet in the tabular arrangement given by Prof. Prestwich (p. 175) we have the ‘‘ White Lias and Sutton Stone Beds” with A. angulatus, Lima gigantea, ete., placed below the zone of Ammonites planorbis. The White Lias is distinguished from the Lower Lias by the absence of Cephalopoda, while it contains Cardium Rheticum, Pecten Valoni- ensis, Lima precursor, and species of Pleurophorus, Aainus, etc., that link it with the Avicula-contorta shales. Moreover, at the localities mentioned, where the surface of the Rhetic beds is said to be eroded, it is above the White Lias that this “slight break” locally occurs. A tabular list of the Lias zones is given (pp. 182, 185), including those of A. opalinus and A. Jurensis, the Midtord Sands being taken in with the Lias, although regarded as passage-beds between that formation and the Inferior Oolite. In this table A. capricornus should come below A. margaritatus. We are glad to see that Prof. Prestwich prefers the old generic name of Ammonites to the many subgeneric names introduced by some paleontologists. Sea LMT °° a, Surface soil. 1’—2'; b, Chalky loam and sand, with small lines and lenticular beds of gravel. At the southern or lower end of the digging the gravel and sand is looped into the top of the underlying Chalk-marl. 6’—7’ ; c, Chalk-marl ; d, Cambridge Greensand ; ¢, Gault. The gravel does not appear on the 1-inch Survey Map, probably because at the time that map was made there was nothing at the surface to distinguish the loam which belonged to the gravel from the decomposed surface of the marl, etc. In subsequent phosphate 198 Mrs. McKenny Hughes—Pleistocene Mollusca. diggings, however, on the north-east side of the village, this deposit was exposed and described by the Rev. O. Fisher,’ and referred to in the Survey Memoir.’ About a mile and a quarter W.S.W. of these pits, north of the Windmill, on the other side of Barrington Green, extensive excava- tions for phosphate have recently exposed other sections in what is the continuation of that terrace, or if now cut off from it by the little valley west of Barrington Green, was originally part of the same. From the character of the workings, the whole of the deposits belonging to the gravel age can be seen down to the base, where they rest upon the Chalk-marl (see Section Fig. 5). They consist largely of materials derived from the Chalk-marl and from the Boulder-clay, which at that time must have covered a much wider area than now on the adjoining hills. A somewhat larger admixture of far-travelled fragments from the drift might be expected, and as a matter of fact is generally found, in all gravel deposits of the district which occur on higher and older terraces, or nearer the hills. The portions of the Barrington Gravel, which are of the same coarseness as that of Barnwell, do not differ much from it in com- position ; in both cases a large proportion of the material consists of ferruginous subangular flints. The Barrington deposit is exceptionally rich in the number and variety of its Mammalian remains. Small pieces of bone occur through the whole, but the largest and best-preserved bones lie in irregular masses of gravel near the base. In one place just above the Chalk-marl there was a boulder of quartzite about 9 inches in diameter resting upon a large limb bone. The bones are generally scattered and mixed, but occasionally there seems to be evidence of associated remains. Among the valuable specimens secured by Mr. Keeping’s skill for the Woodwardian Museum, there are several whole lower jaws of Hippopotamus and a nearly perfect skull of Hyena. It will be seen on comparing the lists of fossils given below (p. 202), that the Mammalian remains from this pit at Barrington (Column IV.) agree with those from Barnwell Abbey (Column I.), with the exception of Arvicola, determined by Mr. Oldfield Thomas, which has not been found at Barrington, and of Reindeer, the occur- rence of which at Barnwell rests on the determination of a small fragment of antler. Horse occurs in all four localities. Bison priscus, Cervus megaceros, C. tarandus, Hippopotamus amphibius (major), Rhinoceros leptorhinus, and Meles taxus, have not been found at Grantchester, but these diggings were unfortunately not so carefully watched as they might have been. Bones have been obtained from the pit near Barnwell Station, but they have, gene- rally, been too fragmentary for determination. The following species have, however, been made out, Red Deer, Mammoth, Rhinoceros and Horse. At Barrington the shells occurred in rapidly thinning and thicken- 1 Q.J.G.S. vol. xxxv. 1879, p. 670. 2 pp. 94-5, Mrs. McKenny Hughes—Pleistocene Mollusca. 199 ing beds of loam and sand in the same manner as at Barnwell Station, but not indiscriminately through coarse gravel and finer deposits as at Barnwell Abbey. The shells of Barnwell Station (Column III.) and Barrington (Column IV.) seem to represent marginal deposits such as are seen along the edges of ponds and rivers at the present time, occasionally encroached upon by river floods which swept them into holes and embayed corners. This is suggested by the accumulation of the smaller and lighter shells, just as now seen on the edge of the flood-water, and by the great abundance of Pupa marginata, while the rest of the shells are quite consistent with this view. Anodonta is rare and usually imperfect. ; The shells of Barnwell Abbey (Column I.) and of Grantchester (Column II.) seem to belong rather to the main channel of the river. Unio and Corbicula, which like river-beds, occur at Barnwell Abbey and Grantchester, but not at Barnwell Station or Barrington. Pupa, the characteristic shell of the other two localities, is comparatively rare at Barnwell Abbey and Grantchester. There is a marked agreement between the Barnwell Abbey and Grantchester Mollusca. All the species which are individually numerous in either locality are common to both. Those which are peculiar to one of the two localities are rare forms. Thus Hydrobia marginata, Mich., occurs at Barnwell Abbey, but has not been found at Grantchester. Limaz is recorded only from Barnwell. Single specimens of Planorbis nitidus, Miill., P. fortanus, Light., Patula ruderata, Miill., Helia lamellata, Jeff., Vertigo pusilla, Miull., V. edentula, Drap., V. minutissima, Hart., and Cecilianella acicula, Mill., have been found at Barnwell Abbey and there only. On the other hand, Planorbis nautilus, Linn., Helix obvoluta, Mill., and H. aculeata, Mill, are as yet peculiar to Grantchester. A more careful search would, however, probably result in filling up most of the gaps in both lists (see pp. 200—202) :— I must here acknowledge the kind help which I have received from Mr. Cooke in drawing up the list of shells, and in finding the range of various species. I am also much indebted to Mr. Dewick for the trouble he has taken in determining my specimens of Limaz and some other species, by comparison with those in the Natural History Museum, and also for lending me his rarer specimens for examination. Professor Rupert Jones has kindly determined the Ostracoda for me. He remarks that he has found Candona compressa, Koch, in Post-Tertiary beds in Berkshire, Cambridgeshire, also at Fisherton, near Salisbury, from the raised beach of Portland (Prestwich Coll.), and from the Chara Bed near Hitchin (Blackmore Coll.). Candona candida, Mill., he says, is very common, both Recent and Post- Tertiary. An explanation of the isolated or rare occurrence of certain forms in the ancient river deposits is suggested by what is seen at the present time along the Cam above Cambridge, where the artificial 200 Mrs. McKenny Hughes—Pleistocene Mollusca. = let cl 6 LisT OF FOSSILS FROM GRAVELS IN THE NEIGHBOUR- hy s 58 i) HOOD OF CAMBRIDGE. Fo| 2 /&s| ce QS} s [m4] 3 6 faa) I. | II. | IIL.) IV. PLANTS. SporesandestemsrotiG/ara we wamen een cei sunset ey xX Salix (probably S. repens). Twigs and leaves. cress x INVERTEBRATA. CRUSTACEA (OSTRACODA). Cypris reptans, Baird (see Jones, Post-Tert. Entom. 1874, TOMY Ce) ey ret etan el A DP Pe LS oi gal a Candona compressa, Koch (20. p. 135). css Xx candida Miill. (26. p. 135). ssrseseeenee x INVERTEBRATA—MOLLUSCA. LAMELLIBRANCHIATA. Sphertum corneum, Linn. (Not very large, mostly young. )..... Xi eee a x SHCU Ste ANU Yio roy itus e uiemeeer ee es i ee x Pisidium amnicum, Mill. (Very abundant. Valves adh.) | x | x | x | x Jontinale, Drap. (Abundant. Valves adherent.) | x | x | x | x var. Henslowana, Sheppard. (Abundant ataGrantchestery) mmewerees scene ciency ian rer eee pra 8 AI Con x pusillum, Gmel. (In Mr. Dewick’s and also in Mr. Tomlin’s Collection from Barnwell Abbey. Several specimens in the Woodwardian Museum fromuGramtchesters) Mcrae nee 0 eX Corbicula fluminalis, Mull. (Usually of a small size. Great variety in size, shape, texture and sculpture. Very abundant at Barnwell Abbey and Grant- chester. Valves often adherent and ligament DT CSETV.CCIN) iene tre ncretere te tore MRNA MELE IS REA eed 6.1) 28 Gnzoprctorceza, Nein ny yee sent taste nec ceseetee ts mS) |) 28 ———._. ———_ var. limosa, Nils. x x hitoralis, Lamk. = U. rhoniboideus, Schrot. (Great variation in size, shape and thickness. Both valves often adherent and ligament preserved. )..... Kx ATOM OPLG Spas \erstterstse esau ret atte esaaead ecgctect tiene aged tor ototatanvcet hee | here | eeeeeema Mee x GASTEROPODA. Bythinia tentaculata, Linn. (Varies much in size. Many young specimens. Opercula very common in places. Sometimes found still in the shell.) .......... Die cues x iyarovia marcipata, IMichwy ai (Raves )esenten ee eee x Valvata piscinalis, Mill. (Very abundant. Varies very much in size and shape. Many young specimens.) ..... Saori |fe bre I] sx eristala, Mill. (@Nioticommion.)) erect cissccrscvevesssstes Keath ieee xs Planorbis nitidus, Mill. = P. dineatus, Walker. Very rare. (One specimen in Mr. Tomlin’s Collection.) ..........| x ————- fontanus, Lightf. = P. nitidus, Mill. (Jeff.) British Conchology, vol. i. p. 81. Mr. Dewick has a single specimen in his Collection, from Barnwell. | x ACIS (yy 01 a pease oa ae IT RAS aR AE A xd podabermalie tia. \(\VieGyaranes) ee ee eee ae re || 3x spirorbis, Mill. (Commonat Barnwell Junction.). | x | x ) x ) x Borpags, Meas) \ (OREN) kere cecemmoancemtineniasenams I OS |) 28 CanimatusmiMnall ss ((Rares)iee crs onses Se Ul Seal) Ske complanatus, Linn. (Fairly abundant.) go Mrs. McKenny Hughes—Pleistocene Mollusca. GASTEROPODA— continued. TAULOLO US COMLO LLU WlTitisy) (NATE) i ierescecestesscecsentsssssscecoctzessecotececnved Physa hypnorum, Linn. (Single specimen from Grant- chester, in the Woodwardian Museum. One specimen from Barnwell Abbey in Mr. Tomlin’s (Coos Mexet (0) 015) \ rere reer acer scene cere nee fontinalis, Linn. (Three or four good specimens from Barnwell Abbey in Mr. Tomlin’s Collection, and one specimen from Grantchester in the Woodwardian Museum.) .......... Limnea peregra, Mill. (Not common.) auricularia, Linn. (Very common. Spire often much intorted. Two specimens from Barnwell Abbey slightly scalariform. Varies much in size. Lines of growth often strongly marked.) ss... stagnalis, Linn. (A few specimens only from Barn- well Abbey. Fairly common at Grantchester-. )..... PROLOG cecclecrorceccer tc occoneno cone ineatbas Gorm Coe truncatula, Mill. (Common at Grantchester. Miamys veryasmaalllispecimlems.)) esscscccssasecssacessuceeeccocersecs A ees Jerviaatiles, Mild. .escseeeesessensseesnsessesesensssenemneennasesnsneessaneein lacustris, Linn. = oblongus, Forbes & Hanley. .... LAND SHELLS. LE (OES: CRGAGSLI, MANAG ech erect crtreorarie eee erred pee arborum, Bonch. Chant.’ (Mr. Dewick determined EVONSPECIMenS| fouMa bys We.) ieescccssseqeevessssecessssa st secesesses levis, Mill. (Two specimens found by myself.)..... Succinea putris, Linn. (Very large specimens at Barnwell Abbey and Grantchester. ) HERI PS UTS O GR: creases reson pearance ete ———_ oblonga, Drap. «0. Flyalina cellaria, Mill. «es. i nitidula, Drapipsen: ramon radiatula, JMG ESS eee yeec easy cera eter tence peter reyo nitida, Miill. Pe ea lp a pp crystallina, Miill. .. CORLIES jf Wea Oy eereecerercrect erect Patula rotundata, Mill. (Rare.) ruderata, Studer. (A single specimen found by VASre2te TB) wi Clk) aeons ni a re Se See Pleo —— pygmea, Drap. (One reversed specimen found at Barnwell Abbey by Mr. Dewick.) ....ccscsssssssccsseee Helix (Anchistoma) obvoluta, Mill. (One full grown and one young specimen in the Woodwardian Museum. ) (Acanthinula) aculeata, Mill. (Twelve specimens in the Woodwardian Museum.) -.........ssssssssccsessseeseeneees (————) /amellata, Jeff. (A single specimen found Doivgul Urge) Swi Kea) pee sccseceeceessesserere terccmrestsacs sescecronsscersesereses (Vallonia) pulchella, Mill. (Very abundant.) (CLALIT) TOG ES NOW 5 cecerrcerchenctscecee erp oreo EeOr ) concinna, Jeff. (One reversed specimen found at Barnwell Abbey by Mr. Dewick.) ......... (———) riticures, Mill geal (RAKE. ))scctcccssscssssstcerscsee (Chilotrema) lapicida, Linn. (Three specimens from Barnwell Abbey. One in Mr. Dewick’s Collection and two in the Woodwardian Museum. Two specimens from Grantchester in the WicodwarcliamelViuseim) Wesctentscetcecteser resets (Arionta) arbustorum, Linn. (Varies very much. Many of the shells distorted and injured..)............... (————-) var. alfestris, Ziegler. (Common at Barrel PAID De yay) ie secesecessnsrensesereertcrvtarsssrtectoscesecsvenccrtestestsrie I. x II. x nn KKK MMM III. a 201 202 Mrs. McKenny Hughes—Pleistocene Mollusca. WW . | ail 4 lal & List oF FosstLs FROM GRAVELS IN THE NEIGHBOUR- |2®| ¢ || %& HOOD OF CAMERIDGE—continued. ES S/ES| cc ea) 3 |Q4)] « & aa) My ables Ode. || W's Flelix (Tachea) mnemoralis, Linn. [Not very common. Varieties of banding, 12345, 00345, (12345), 1(23)45, 00330, 003(45), 10345. | nssssssessssssssssssssessesesecese Koel sexeyliipeers x (Xerophila) cricetorum, Mill. (Common at Barn- wellvAbbeyanda(Gramtchester.))) 0 fess.sersocserseerseereess Sar ors nil eree |p. 3 (————_) virgata, DaC. (Commonat Barrington.) | +... | a. | we x Se (ae) CO Denaro. Monts) (Very rare.) PGI Niel Gin lleecaees ? LEU PT EOES TROGLECIORS, JONCEND, * scocerceececereccricoeee oe rere x x x obscurus, Mill. (One specimen from Barnwell Abbey in the York Museum, and one from Grantchester in the Woodwardian Museum.) .... x |) se Pupa marginata, Drap. (Very abundant at Barnwell Station ang eat a arrin Seo my figs teseceestscestas sessed tssesteseeecesrstee ogy oe ose |) 3g VCHUCOONUPULTU CHL LEON MOT AT) Nag corny semen ee tencscsreernassettcssnecorstateseccasesesies x ex ; cea VL OTLLL TOS ZC 72 MMB) ALD Ulsyeapenererete eerasseecss nstsiceascrrsvarcteeeesssrtesretss 5 (es pusilla, Mill. (One in Mr. Tomlin’s Coll.) HEINER. QULUSTLO MANIC hat can teeta ra ete ietirciiie eres csresttatec xn (GG DY UIE DA Va pecrcecsct eset aste a iat eatetenactesst ove doheternvem tencat settee x || ox edentula, Drap. (One found by Mr. Dewick resembles var. colunzella of Jeffreys. ) secs x minutissima, Hartmann. (One specimen found by VED ei Ce eee eee ne nua eis x Balea perversa? Linn. Young. Mr. Dewick’s Coll... | X (CUA SHEGS FONROS Dy JOVEN Os cereecececceeccctbcca cxrcce ecereeeeeectea eee oan x x = pumila, Ziegler. (Described in former lists as CEU DYTATTATION) setoeres eur renee ete eRe Pe eh Oe Azeca tridens, Riet. (Rare.) eos | eee Xs LEAR UAE Bape IRC ect cg erecta ener et cee eee cee am pace anf as:e il Sie Cecilianella acicula, Mill. (One specimen found by Mr. Dewick. Young. Filled with gravel.) osc Xa Waexe Carychium minimum, Mill. (Common. Several of the specimens found inside A. arbustorum and TLCTRUO TO BS) Nirrec atria eaten Woa ces ar itlaeotaats acer eo Xen ex Cyclostoma elegans, Mill. (One specimen only, found by me in the Mammaliferous gravel of Barrington.) .... | wee | owe | oo x VERTEBRATA. Lison priscus, Bojan. 0. ects Secteusnusrtsstssasesiate Ala ccs [ieee x Los primigenius, Bojan. .... pod iby ia x Cervus megaceros, Hart. srs. C4 eco x = elaphus, Linn. ....... Xo UE xc Al) exaad|faeexs tarandus, Linn. pp | 2 DEV EDO SHOPLET UUS WAG sami te ete teatime ae Hc eed ee x erp (7.0 IE LCCTLLOLS | SULLA ay pesos rtececesctccecse nase sestssnececeasiaastontcisctersbar poh org Mi |) 98g 0 5 Liquus caballus fossilis, Meyer. rg iss) 38) 3S Peep CL@a™ (Gold fe, Vitti nae MAM at GER Re eRe ne Oe aia x KP alles xe Ffippopotamus anrphibias, Li. = MAZOr, CU. verecrsseereerserrrnrinnen I, lisercossat | Gee x Flye@na crocuta = spelea, Goldh. crececccccscsn creer Becta tee [oS cee x Rhinoceros leptorhinus, ox tichorhinis, CUviel. screen prea (| tba OR || OK GG SUSESPETE US IVAN | 222 cok eas ne ee tater eee ete Xe | xen eae x Meles taxus, OWEN. esse... pe a ea oa Cee x Arvicola agrestis? sp. SG | 8 Mrs. McKenny Hughes—Pleistocene Mollusca. 203 diversion of the river has produced effects which must have been common in the case of the uncontrolled rivers of former times. On Sheep’s Green there are many small ponds which represent deserted portions of the old river-bed; in these many of the less common and irregularly distributed freshwater shells occur—abundantly in one—rarely, or not at all, in another. For instance, we find Bythinia Teachii there, as well as in the ditches further south. In one of the ponds seven species of Planorbis, including the two rare forms P. nitidus, Mill., and P. fontanus, Light., also Valvata cristata, Mill. and many of the Pisidia, are found. Mr. Tomlin, who has thoroughly searched that locality, informs me that two of the ponds are far richer than any of the others, and that he never met with the two rare species of Planorbis, mentioned above, elsewhere in this neighbourhood, except odd live specimens in some of the other Sheep’s Green ponds. He never found them anywhere down the river. Along the margin of these pools Carychium minimum, Mill, and Hyalina nitida, Mill., abound. Now and then, when the river is in flood, the whole Green is under water, and at such times many of the shells in these ponds and ditches must be carried away and mixed with the common river shells. From analogy, therefore, it would appear that the winding about of a frequently flooded river, over an alluvial plain, in which ponds remained where the deeper parts of the old river-bed had been, would most easily account for the difference in the facies of the gravel-shells in the different localities. A careful study of the distribution and mode of occurrence of the gravel fauna and flora ought to give us some clue to the geographical changes which have affected the incoming and disappearance of the various forms of life. The great majority of Mollusca from these gravels are living in this district at the present day. A few are locally extinct. Of these some are confined to the north and some to the south of England, whilst some have disappeared from the British Isles altogether. Some of the Mammals, but none of the Mollusca, are totally extinct. The shell which seems to indicate the greatest change of con- ditions is the Corbicula (Cyrena) fluminalis, Mill. It lives at the present time in Sicily,’ in the rivers of Asia Minor and Syria and in the Nile. It seems to have made its first appear- ance in Britain in the time of the deposition of the Norwich Crag, from which it is described and figured by Mr. Searles Wood,” as Cyrena consobrina.’ It is recorded from the Weybourn Crag and from the Forest Bed. In the north of England it is found in the gravels of the Humber, of Kelsea Hill, and Hessle; in the basin of the Thames and the adjoining district of Essex it has been recorded from Suttonness, Clacton-on-Sea, Copford, Greys, Ilford, Erith, and Crayford, Faver- 1 Geol. Eng. and Wales, H. B. Woodward, 2nd edition, p. 478. 2 §. V. Wood, ‘‘ The Crag Mollusca,” vol. ii. p. 104, tab. 11, fig, 1. 3 Tylor, Q.J.G.S. vol. xxv. 1869, p. 66. 204 Mrs. McKenny Hughes—Pleistocene Mollusca. sham and. Reculvers, and by Prof. Prestwich! from Summertown near Oxford. It also occurs in the gravels of the basin of the Cam and Ouse. It occurs in Belgium and in France in the ancient alluvium of the Seine and Somme. ‘This therefore appears to be a southern shell, which had formerly a more northern range. The six following shells are extinct in Britain, but most of them have a wide range in Europe and Asia :— Unio litoralis, Lamk., is, according to Moquin Tandon,? found in almost all the rivers of France. Kobelt records it also from Spain, Morocco, and Algeria. Unio pictorum, var. limosa, Nils., according to Moquin Tandon, occurs in almost all the rivers and brooks of Northern France. Hydrobia marginata, Mich., lives in France, says the same author, on dead leaves under water and on aquatic plants at Var, Vaucluse, L’ Aveyron, the Haute Garonne and the Jura. Helix (Frutieicola) fruticum, Mill., is found all over Turope with the one exception of England. It ranges as far north as St. Peters- burg.’ Moquin Tandon‘ says that it is found over almost all northern and central France, but that it does not occur in the southern part. Miss Esmark records it from North and South Norway, Sweden, and Finland. She says, “It is not very common, but plentiful where it occurs.”° Iam told by Mr. Cooke that it occurs also in North- West and East Siberia and the Altai Baikal district. Patula ruderata, Studer, has a very wide range. Kobelt records it from the Caucasus, Europe, Northern Africa, and the whole of Western Asia. Jeffreys from Kamschatka, South Russia and Austria, and North Japan.® Clessin says that it lives in the mountainous parts of Germany and in the Alps. Moquin Tandon says it is found under stones and dead leaves in the Jura. Miss Esmark records it from Norway, Sweden, and Finland, and remarks that it is “one of our most common species, which goes as well to the far north as on our highest mountains, wherever it is possible for any Molluscs to live.’*? Mr. Cooke informs me that it is found also in West and Hast Siberia, Amurland, North China, Japan ? and North Persia. Clausilia pumila, Ziegler, is, according to Clessin,® distributed over a great part of Germany, but is most common in the North. Its range is eastward to the Siebenbtirgen; southward to Croatia ; northward to Livland and Sweden; it finds its western limit in Germany, and does not occur in England except as a fossil. It has hitherto been recorded from the gravels of Cambridge as C. biplicata, but Mr. B. B. Woodward® has shown that all the shells referred to that species are really the C. pumila of Ziegler. 1 Grou. Mac. n.s. Vol. IX. 1882, p. 49. 2 Hist. Nat. des Mollusques. > Clessin, Deutsche. Excurs. Mollusken-Fauna, p. 166. 4 Op. cit. vol. il. p. 198. 5 Esmark, Journ, Conch. vol. v. pp. 106, 126. 6 Jeff. Brit. Conch, vol. v. Supplement, p. 158. 7 Journ. Conch, vol. v. p. 104. 8 Op. cit. p. 312. 9 Since this paper was sent to press a valuable communication has been made by Mr. Woodward to the Geol. Assoc. (March 2, 1888) on the shells of the Barnwell Gravel, founded chiefly on Mr. Dewick’s Collection. Spheriwm lacustre has been inserted above on his authority. Mrs. McKenny Hughes—Pleistocene Mollusca. 205 There are also in the gravels described some six or eight shells which we do not now find in the neighbourhood of Cambridge, but which occur elsewhere in the British Isles. Succinea oblonga, Drap., is mentioned by Gwyn-Jeffreys! as rare in Wales, Scotland and Ireland and in England is recorded from Braunton Burrows in Devonshire only. Its habitat is “‘ dry ditches near the sea-coast.” Helix (Anchistoma) obvoluta, Mull. This shell, says Jeffreys, lives on stumps and at the roots of trees in woods in Hampshire. Da Costa and Taylor give it a somewhat wider range in the south of England, mentioning also Surrey and West Sussex. Jeffreys observes that it occurs in France, Germany, Switzerland, and Lombardy, but that it does not seem to inhabit the extreme north and south of Europe.’ Clessin says that it is less common in the north than in the south of Germany, and he records it also from Bohemia.’ This occurrence of H. obvoluta in the gravels shows that it is not a form now advancing from the south, but is, on the contrary, a species which is dying out in England, but still survives in the south. Helix (Acanthinula) lamellata, Jeff., is now found only in the north of England, Anglesey, north and west of Scotland, Ireland, Sweden. Clessin‘* records it from North Germany. In this shell we have, in contrast to the last-mentioned species, an example of a form which has become extinct in the south of England, but is still fairly plentiful in the north. Vertigo angustior, Jeff. The habitat of this rare shell is “in the roots of grass in marshy ground.” Jeffreys found it near Swansea and in the rejectamenta of the river Avon at Bristol. He records it from Tenby, Battersea Fields, and Ireland, the north-east and south of France, Germany, Switzerland, and ov Lugano in Italy.° Mr. Charles Ashford, who kindly examined a specimen which I had discovered at Barnwell, found on comparing it with recent Vertigo pusilla in his collection from Yorkshire, that amongst them was one undoubted Vertigo angustior which he had hitherto over- looked. I have found it in Westmoreland also. Miss Esmark records it from South Norway and Sweden.® Possibly the following species did not appear in England till after the deposition of these gravels. Helix (Fruticicola) cantiana, Mont., does not seem to occur in the gravels. It is very common round Cambridge at the present time, and is found in the north and south of England, but not in Scotland or Ireland. It lives in France, Belgium, parts of Germany, Italy, Illyria, and Sicily. It is doubtful whether Helix (Fruticicola) rufescens, Pennant, is found in the gravels. It is now widely distributed over England, and occurs in Ireland, but not in Scotland. Helix aspersa, Miill., is not recorded from any of the localities 1 Brit. Conch. vol. i. p. 154. 2 Op. cit. p. 230. 3 Deutsch. Exe. Moll.-Fauna, p. 134. £ Op: cit. p. 129. ° Brit. Conch. vol. i. p. 266. 6 Journ. Conch. vol. v. p. 127. 206 Mrs. McKenny Hughes—Pleistocene Mollusca. given in the list, nor can I find mention of it from similar gravels elsewhere. Mr. Gloyne in his paper on the Geographical Distribution of the Mollusca,' says, “‘ Helix aspersa attains a much larger size in Italy than in England. It is very difficult to believe that so abundant a British species has been introduced; but judging from the reduced size of English specimens, England would, to say the least, not appear to possess the most favourable climate for this mollusc.” Jeffreys says, ‘It does not appear to inhabit the north of Europe, nor Germany. . . but its range extends southwards through France to Sicily, as well as to Spain, Algeria, and the Azores.’ Tt occurs also in many widely separated parts of the world to which it is known to have been artificially introduced. As, for instance, Mauritius, 8. Australia, Valparaiso, Rio in Brazil, and sea-ports along the east coast of N. America. The only evidence we have bearing upon the time of its first appearance in Britain is its — plentiful occurrence in the Roman rubbish pits at Chesterford and elsewhere about Cambridge at such a depth and in such a manner as to preclude the possibility of its having got in subsequently.® Helix? pomatia, Linn., which lives now in the neighbourhood of Shelford, has not been found in any of these gravels, and I have never noticed it among the Roman remains of this district, even where shells of #. aspersa appear to have been thrown inin large quantities. Heliz (Arionta) arbustorum, Linn., is now found with Helix (Tachea) nemoralis in the Grantchester woods. It also lives under the willows close to the river, and is seldom found far from the water. A few days ago I noticed numbers of shells of this snail freshly broken by birds lying round the stones on which they had been smashed, all along the bank of the ditch near the bathing sheds on Coe Fen. ‘This species is extremely common in the gravels of Barnwell Abbey and Grantchester. It probably found a hiding- place as at present under willows, of which remains, as we have seen above, occurred so abundantly in one part of the pit at Barnwell Abbey. Cyclostoma elegans, Mill. I have found one specimen of this shell undoubtedly in the Mammalian gravel of Barrington. It does not now live in the immediate neighbourhood of Cambridge. I found quantities of dead shells, many with the opercula in place, several feet from the surface, in a tumulus of pre-Roman date, at Upper Hare Park, near Six Mile Bottom. It appears, therefore (see pp. 2083—204) that among the shells of the Cambridge gravels we have no fewer than 6 species which are no longer found in Britain. Several species which I have mentioned (see p. 205) have been found in the gravels, but have now disappeared from this district, though they occur in other parts of England, and some species which are common near Cambridge at the present time are absent from the gravels (see p. 205). 1 Journ. Conch, vol. i. p. 289. 2 Brit. Conch. vol. i. p. 182. 3 See also B. B. Woodward, Science Gossip, May, 1883, pp. 114, 237. WC Knight del.et lith. West, Newman&Co.imp, Heterastrea. R. F. Tomes—On Heterastrea, Lower Lias. 207 Tt will be seen, also, that of the locally extinct Mollusca, as in the ease of the Mammalia, some are distinctly northern, some southern forms, and some have an extensive range from north to south. Con- sidering the wide distribution of the forms, both extinct and living, it is not safe, without taking into account the habitat and range of every species, to generalize upon the climatal conditions of the age. The collective evidence which we gain from the Mollusca as to the climate of the period is more reliable than that offered by the Mam- malia, because the various northern and southern Mammals could migrate to and fro with the changing seasons; but the molluscs once having found their way to a locality would remain there until they were “slowly driven away by unfavourable conditions. The two shells of most pronounced southern origin, Corbicula fluminalis and Unio litoralis, being fresh-water forms, Sonia not be affected by changes of temperature so soon as land-shells. With regard to geographical changes, the whole gravel fauna seems to point to continental conditions, when Europe was connected with Africa, and England was united with France and Belgium. The formation of the British Channel would put an end to the migration of the larger animals, and would cut off the species, which had here reached their furthest limit, from the region of their greatest development. These species, being thus isolated, would in time give way to the more vigorous forms, which were better fitted to their surroundings, and would not be affected by such changes. I].—On Hererastr#z4, A NEW GENUS oF MADREPORARIA FROM THE Lower Ltias. By Roserr F. Tomss, Esa. (PLATE VII.) URING the interval of ten years which has elapsed since my paper on Liassic Madreporaria was read at one of the meetings of the Geological Society, a great many specimens of Liassic Isastree and Septastree, chiefly from the Vale of Evesham, have come into my hands, and with this abundance of material I have examined anew the several species, and have arrived at the results contained in the present communication." When making these examinations, I have been invariably struck with the absence of a distinct and well- defined basal wall and epitheca. Further observation also showed that these Liassic forms differed from other Isastree in having occasional elongated calices, like those of Latime@andra. With the latter genus some of the Liassic Isastre@e@ were supposed (though as it now appears erroneously) to hold a near relationship, and one species received the (at that time) appropriate specific name lati- meandroidea. With this the supposed resemblance ended; for gemmation, which in Latimeandra is calicinal, was found to be always marginal in the Liassic forms.’ Fuller investigation brought to 1 More than seventy specimens have been examined and contributed to the results made known in this paper. 2 It has become necessary that gemmation in the genus Jsastr@a should receive further attention. It has been variously stated both by Prof. Duncan and by me to 208 R. F. Tomes—On Heterastrea, Lower Lias. light other characters. A great development of endothecal structure sometimes almost filled up the loculi, and the walls of the corallites were observed to be of great thickness. Horizontal sections gave the proper interpretation of these thickened walls, and it was often seen that there was not only a fine line where the walls of the coral- lites came in contact, but that there was occasionally a visible interval between them. In this particular they resembled Septastrea, while at the same time their increase was by gemmation. Closer observation revealed the fact that there was both gemmation and fissiparity in nearly all the species examined; and, in a word, that they possessed characters which were inconsistent with both Isastrea and Septastrea, and formed a group of themselves. Before proceeding to define the characters of the group above indicated, I take the opportunity of making some remarks which bear, though only generally, on the species under consideration. Having repeatedly, both on former occasions and in the present communication, followed Milaschewitsch in the use of a word which is rendered in English by the word rejuvenescence, I am induced to give the following explanation of the process, because it is absolutely necessary that there should be a very clear conception of its impor- tance in one of the genera of which I shall speak. That genus is Elysastrea. ‘That it is not merely intermittent growth, and that it is not gemmation, has been most clearly shown by Milaschewitsch, but what really gives rise to it has not been explained by him. It was certainly noticed by Ehrenberg, and was long ago known to Dana, though he does not appear to have fully understood its nature. In the third volume of the American Journal of Science (second series) he speaks as follows :— “In some Cyathophyllidz the process of death goes on inter- ruptedly, as explained by Ehrenberg. The tissues of the polyp disappear at intervals from the sides of the corallum, or become dead, leaving a row of unoccupied cellules; then the animal goes on to increase from its contracted size, without refilling the cellules; the corallum consequently becomes covered with encircling ridges, or appears as if formed of a series of inverted cones. In some cases, as in the species referred to the genus Strombodes, the living portion becomes retracted at intervals to the very centre, all the rest dying, and afterwards the animal grows again and spreads to its original take place within the calice, as well as on the margin of the wall which surrounds it. Thus in the descriptions of IJsastrea endothecata and I. latimeandroidea, Prof. Duncan says it is marginal (‘‘on the margin’’ are the words made use of in the description of the latter species). More recently, however, he has asserted that ‘‘ the gemmation of Jsastrea certainly does not take place between the walls of corallites, but within the calicular margin; it is between the margin and the centre of the calice.”’ I am not aware that it has ever been spoken of as occurring between the walls, though I, as well as Prof. Duncan himself, have spoken of it as occurring both inside the calice and on the margin of the wall.. MM. Milne Edwards and Haime (Hist. Nat. Coral. vol ii. p. 626) speak of it in these words, ‘‘ Les polypierites se multiplient par gemmation calicinale et submarginale,’’ while M. de Fromentel says itis ‘‘submarginale.’’? The present communication by removing the Liassic species from the genus Jsastrea altogether, will materially lessen the difficulty of future classification. R. F. Tomes—On Heterastreea, Lower Lias. 209 diameter, and thus it forms actually one low inverted cone upon another. This peculiarity (probably an occasional result of the exhaustion which follows reproduction) cannot properly be con- sidered a generic distinction.” In his “Structure and Classification of Zoophytes,” page 65, after speaking of the process of dying or removal below, he says, “ It is obvious from the preceding, that the polyp, which is the germ of a compound Zoophyte, loses its identity, and cannot be said, in any proper sense, to have the long life which is attributed to the full erown Zoophyte itself; or else we might have among the huge Astraeas of the Red Sea, polyps that were contemporaries with the builders of the Pyramids.” The polyp, however, ‘which is the germ of a compound Zoophyte,” may lose its identity, and most likely does, by the process of gemmation, but not by rejuvenescence, which under no circumstances, as explained by Milaschewitsch, increases the number of corallites, and it is certainly rejuvenescence, of which Dana was then speaking. It is when the contraction of the polyp takes place very irregularly, that the true nature of the process becomes most easily determined. If the shrinking of the soft tissues of the polyp is wholly on one side, and very great in degree, so that the visceral cavity is drawn out of the centre of the calice, then the constricted side of the animal will be lifted out of the loculi in the process, but that side which has undergone no such contraction may be very little interfered with. In such a case entirely new septa will be formed on one side of the now-expanding calice, while on the other side, no new ones will be produced, nor indeed needed, the old ones being still in actual use. The contraction may, however, be, and it often is, just sufficient to leave vacant only those loculit which have been formed by the later developed septa, and then there will be the full number of cycles on one side, while on the other the primary septa only will be present. As observed by Dana, rejuvenescence is not of generic importance, and he might have said that it had no specific value, in which respect it differs widely from gemmation, which has not only specific but great generic value. The Madreporaria of the Trias are very little known in this country, and beyond a few species which occur in the Sutton Stone of the Glamorganshire coast, we have to refer chiefly to Laube’s descriptions and figures of the St. Cassian species. An examination of the compound genus Elysastrea reveals a very curious septal arrangement. This I will now proceed to consider, and it will be desirable that I should, in the first place, quote from Laube some part of his generic description. He says that gemmation takes place within the calice, and resembles that of Heliastrea.'_ He then goes on to state that the young individual separates itself by a little 1 MM. Milne Edwards and Haime define the budding in Heliastrea in the following words: ‘‘ Les nouveaux individus produits par bourgéonnement se montrent dans les differents espaces intercalicinaux.’’ Probably gemmation in Elysastrea also took place in the intercalicular spaces. DECADE III.—VOL. V.—NO. V. 14 210 R. F. Tomes—On Heterastrea, Lower Lias. wall by which the calice acquires the appearance as if a double wall were present, as in the Paleozoic genus Acervularia. By degrees the margin extends itself, until it blends with the thick surrounding margin of the older calice. Laube’s figure illustrates the process above described. But both description and figures will apply with greater accuracy to rejuvenescence than to calicinal budding, which process in Acervularia, to which that of H'lysastrea has been likened by Laube, is a process of multiplication, and in neither his description nor in the figure is there the slightest indication of an increase in the number of the corallites by calicinal budding. On the contrary, there are many small calices appearing amongst the larger ones, just as they would appear were they the result of marginal instead of calicinal gemmation. Prof. Duncan, in describing the South Wales Elysastree, says that the budding is extracalicular, but that the bud probably has its origin in the centre of a corallite. No evidence is however adduced in favour of the latter supposition. None of my specimens from the Sutton Stone exhibit the budding process as it is shown in Prof. Duncan’s figures, i.e. between the corallites; but they have rejuve- nescence just as in Laube’s figure. The young calices between the old ones in Prof. Duncan’s figures are just such as would proceed from marginal gemmation in a genus in which the corallites are imperfectly united by their walls, and I have little doubt but that gemmation in Hlysastrea is marginal, as it is in the so-called Liassic Isastree. The nature of the endotheca in the South Wales Elysastree is very apparent and closely resembles that of the forms which I now bring together under the name of Heterastr@a, in all of which, I may here observe, it is so very similar, that I do not find that it affords even so much as a specific difference. Vertical sections show how very similar it is in the several species. There are some of the species which have occasional calices which are almost as free on the calicular surface of the corallum as those of Elysastrea. Isastrea Murchisoni is one of these, and, as men- tioned by Prof. Duncan, some of the corallites are so much elevated above the others that there is “a faint trace of a subsequent growth of wall,” by which I presume it is meant that there is an addition made to the wall after it has been formed. As will be hereafter mentioned when speaking of the species, there is also rejuvenescence in Isastr@a Murchisoni, as there is in Elysastrea. Bearing in mind all the foregoing considerations, I have arrived at the conclusion that there is a rather near relationship between the Triassic genus Elysastrea and the so-called Liassic Isastrea and Septastrea, and that the latter are one and the same generically, and quite distinct from the later Secondary Isastree@ and the Tertiary Septastree. The genus into which I now propose to place the following species, I name and define as follows :-— HErerastRmA, nov. gen. The corallum is composite and massive, and the corallites are R. F. Tomes—On Heterastreea, Lower Lias. PAI united by their walls, but the union is often incomplete, and the line of contact frequently visible. There is an occasional trace of a common or basal wall, with a rudimentary pellicular epitheca, both of which, however, are very often wanting. The endotheca consists of dissepiments which are not vesicular, but flat and more or less tabular, and there are occasionally distinct tabule, many of them passing quite across from wall to wall of the corallite, forming a level floor to the calice. Increase takes place by gemmation, which is strictly marginal, and never calicinal, and by fissiparity, which is first indicated by the elongation of the dividing calices, followed by the appearance of two or more fossule, which are finally divided from each other by the union of two elongated septa.’ The prevalence of gemmation over fissiparity, or the reverse, exercises a decided influence, not only over the shape of the calices, but also to some extent over the general contour of the corallum. The elevation of budding calices above the level of the surrounding ones tends to produce a more gibbous surface than does the division of the calices by fission, and the conformation of the corallum is modified accordingly. This will be further noticed when I speak of the species, which I shall now proceed to do, first enumerating those which I have not had the opportunity of examining. They are :—Isastrea intermedia, De Ferry; I. excavata, De Ferry; I. basaltiformis, Fromentel ; I. Orbignyt, Chap. et Dewal.; I. Condeana, Chap. et Dewal.; I. Moreneyana, Terq. et Piette; I. ? Henacquei, Kd. et Haime; and Latimgandra denticulata, Duncan, all of which have been stated to occur in the Lower Lias. HererastR#A Mourcuisoni, Wright sp. Isastrea Murchisoni, Dunc., Supp. Brit. Foss. Cor. pt. iv. p. 41, pl. xi. figs. 1-4. The only example of this remarkable species, from the Isle of Skye, to which I have access, is small in size, and has but little calicular surface. Yet, small as it is, it has marginal gemmation, and elongated calices which, having more than one fossula, with an indication of dividing septa between them, affords indubitable evidence of fissiparity. Prof. Duncan says, ‘There is often a ridge between the margin of the calice and the centre, indicating calicinal gemmation, but the gemmation usually takes place at the margin, and there is no fissiparity.” The ridge here mentioned has nothing to do with gemmation, but is merely the commencement of rejuve- nescence, and in one calice of my specimen it has proceeded so tar as ' Tt is necessary to notice here a variation in the process of splitting that takes place in different calices, or even in the same calice. The two opposite and approach- ing septa do not always meet and make the division until a new calice has been actually formed, and it is common for two or three fossulee to make their appearance in a long calice with only some, or even without any, dividing septa. When this is the case, there is some resemblance to Latimeandra. However, the septa always become elongated sooner or later, and fissiparity is then complete. M. de Fromentel gives a good account of the process in his description ot the so-called Septastrea excavata. 212 R. F. Tomes—On Heterastrea, Lower Lias. to have given rise to a smaller calice within the larger one, which has a considerable degree of prominence, and bears an extremely close resemblance to some of the corallites represented in the upper part of Laube’s figure of Elysastrea Fischeri. I have met with two ill-preserved specimens of a coral which resembles this species in the size and openness of the calices, the one from a gravel-pit at Charlton, near Evesham, and the other from the zone of Ammonites angulatus, near the village of Church Lench, a few miles north-west of Evesham. HererastR#A Kvesnamt, Dunc. sp. Pl. VII. Fig. 3. Septastrea Eveshami, Dunc., Supp. Brit. Foss. Cor. pt. iv. p. 52, pl. xii. figs. 5-7. By the kindness of my friend the Rev. P. B. Brodie, the type- specimen of this species is now before me. The calices, which are in process of division, or have already undergone that operation, are conspicuous over the whole upper surface of the corallum, but gem- mation, though apparent and marginal, is not frequent; nor is it common, though well marked, in other specimens of this species in my collection. It is a distinct species, and in some examples the specific characters are even more typically developed than in the type itself. They are all more or less flabelliform, but they present every degree of inclination from a nearly vertical to a horizontal position. ‘The finest specimen yet met with has the form of a regularly oval plate, ten inches long, and not more than an inch in thickness. It was attached by a broad space near one end of the under side, which is flat. The calicular surface is horizontal. Fissiparity occurs over the whole of the latter part, but gemmation is by no means common, though, where it appears, it is unmistakeable. This specimen was taken from a quarry near to Prior’s Cleeve, about five miles north-east of Evesham, and its place in the Liassic beds will be best explained by the following section :— Ft. Ins. 1s Surtaceysoil wath| pebbles wabOuti...c.asceeerssecceseecssneasemeese reece 2 0 2loight=colouredaclayspecsnenceranscse sas tecesecascoeeectee eee enuae esse rsereee 11 6 3 Black laminated shale with fragments of shells and Echinoderms, and a specimen of Heterastre@a Eveshami ......1.ccseecseeneeeees 3 6 au induratedidarkvoreygshale) vices sents ce d-sestercocmeeeeceeke cece ceeeeee 0 3 5 Laminated stone with Ammonites planorbis and insect remains ... 0 6 Go aminated shale sy secmeneracenseeat neck sccuasmeenscccathcmnense das omenes 3 3 @ Tadminated stone!) Anas scaenestoss. ss cesce seu sebesn sees estuanoeae see eeer eee 0 7 8 Laminated shale, the upper and lower parts of which are light in colour, and the middle black. The latter is a mud deposit and contains the joints of Pentacrinites, Cidaris spines, and comminuted shelllsWreemeeeemescceceeeecdacsceesseceeeercecemencrecseen 3 3 9 Laminated stone, with Am. planordis........cscececscecscececncsencnenss 0 3 HOWMMamiin ated ‘shale: 15. ies. dsmccuctersnincniecionccteslonct est ceceueneeouse oceans 0 7 Uibaminated Stone’ 2. ces ateatoeekiusec dee seetssaee oneeeea sere os ctoasccna 70 6 26 2 12 Laminated shale, beneath which is the Ostrea bed, depth not ascertained. I have also obtained the present species from Binton, about four or five miles west of Stratford-on-Avon, where it was associated with Ammonites angulatus. R. F. Tomes—On Heterastrea, Lower Lias. 213 HetTerastrma Fromenrett, Terq. et Piette sp. Pl. VII. Fig. 4. Septastrea Fromenteli, Terq. et Piette, Lias Inf. de 1’ Est de la France, etc. —— , Duncan, Supp. Brit. Foss. Corr. pt. iv. p. 37, pl. xi. fig. 5. The example of a supposed Septastrea which was found in. the railway cutting at Harbury, and mentioned by Prof. Duncan, as above, has heen submitted to me by my friend Mr. Brodie, in whose collection it is, and a comparison has been made between it and other allied species. Two contiguous calices of this specimen are very remarkable, for on the margin of one there is gemmation, while the other is divided in half by the process of fissiparity. In no other species, or specimen, have I seen the two processes so closely associated or so obvious. Fissiparity is however much more frequent than gemmation in this specimen. As I have only had the opportunity of examining Hnglish specimens of this species, my observations must be understood to apply to them exclusively, though I have no doubt that the French and English specimens are of one species. HeTmRASTR#A STRICKLANDI, Dune., sp. Pl. VII. Fig. 8. Isastrea Stricklandi, Dune., Supp. Brit. Fos. Cor. pt. iv. p. 54, pl. vill. figs. 1-4. The type-specimen of this species was obtained by Mr. Strickland from the clay-pit of the Chadbury brickyard, from which excavation a considerable number of specimens of so-called Isastree and Septastree were taken, some of which agree very closely with the description of this species by Prof. Duncan. I have not, however, been able to examine the type-specimen. It does not appear to be a very abundant species, only three having come into my hands. Two of them came also from the Chadbury clay-pit, and the other was dug up by a market gardener when trenching his land on the side of the hill north of Evesham on which the battle of Evesham was fought. This species is distinguished, as pointed out by the original describer, by its stout septa and thick walls. The calices are rather shallow. There is no instance in either of my specimens of budding actually taking place, though there are calices which from their circular form and their position amongst other calices have certainly proceeded from marginal budding. Fissiparity is common, and sometimes occurs rather peculiarly. The division of a calice takes place all round it, and a very large lobular calice is the consequence, and when the dividing septa make their appearance, they have a somewhat radiate arrangement. HETERASTRHA INSIGNIS, Dunc., sp. Isastrea insignis, Dunc., Supp. Brit. Foss. Corr. pt. iv. p. 54, pl. xi. figs. 10, 11. The specimen on which Prof. Duncan established this species was obtained by me from the Lower Lias at Lyme Regis, but as the opportunity of making an examination of it since it has become a type has not occurred to me, 1 am compelled to fall back upon the other specimens from the same locality, of the specific identity of which, however, I entertain no doubt. Several similar specimens came into my hands with the one I lent to Prof. Duncan. These I 214 Jao IE T omes—On Heterastrea, Lower Lias. still have, and they have been referred to on the present occasion. They are without doubt referable to the same genus as the other species herein mentioned. HEreRASTR#A ENDOTHECATA, Dunc. sp. Pl. VII. Fig. 9. Tsastrea endothecata, Duncan, Supp. Brit. Fos. Cor. pt. iv. p. 53, pl. xii. figs. 17-21. Of this species the original describer says “the marginal gemmation is frequent.” The figured specimen is now before me, and I observe a considerable number of calices which are elongated and have more than one fossula, as well as marginal gemmation, which is common. The irregularity in the size and form of the calices is due to the operation of these two processes proceeding at the same time. Besides the type-specimen, I have some others taken from the Ammonites angulatus beds of the Lower Lias, about a mile west of Evesham. These examples have a very distinct line where the corallites come together, indicating imperfect union. Hererastr@a Harmer, Wright sp. Septastrea Haimet, Duncan, Supp. Brit. Fos. Cor. pt. iv. p. 5, pl. i. figs. 1-5. In 1860, when my late friend Dr. Wright was engaged in investigating the Ammonite zones of the Lower -Lias, he obtained an Isastrea from the Ammonites planorbis beds of Street, and it was mentioned under the name of Isastrea Murchisoni, at pages 390 and 397 of the paper which followed his investigations. 'The specimen was for some time in my hands, and was afterwards described and figured by Prof. Duncan under the name of Isastrea latimean- droidea. At this time an Isastr@a, said to have been obtained from Evesham, also formed part of Dr. Wright’s Collection, but no mention was then made of it by him, though afterwards, in one of the volumes of the Palezeontographical Society, it was mentioned as Isastrea Haimei, and as I then believed, and still believe, was erroneously stated to have been also obtained from the Ammonites planorbis beds of Street. Instead, however, of its appertaining to that Ammonite zone, J entertain no doubt whatever that it is referable to the Ammonites angulatus beds of the neighbourhood of Evesham. Prof. Duncan subsequently described and figured it as Isastrea Haimei. As I have not recently had the opportunity of examining the type-specimen, I cannot speak decisively of its generic relation- ship, though I do not doubt that it is a species of Heterastrea. Herrrastr#A Tomust, Duncan sp. Pl. VII. Figs. 5, 6. Isastrea Tomesi, Duncan, Supp. Brit. Fos. Cor. pt. iv. p. 46, pl. xv. fig. 20. The type of this species is so indifferently preserved that were it not a well-marked species it would be practically useless for com- parison. But the very thin walls and septa which are apparent, whatever may be the condition of the specimen, will at once dis- tinguish it. As a species it is not by any means uncommon; and I have seen specimens trom several localities in the neighbourhood of Evesham, in addition to Grafton, where the type was obtained. It R. F. Tomes—On Heterastreea, Lower Lias. 215 is a low expanding form, sometimes attaining to a great size. The largest I have yet seen is almost as heavy as a man can lift. On nearly every part of this massive specimen the line where the corallites come into contact with each other is very visible, and in some places there appears to be a slight but perceptible interval between the walls. Marginal budding is frequent, and fissiparous division of the calices is observable everywhere. Some of the calices are more than an inch in length, and have a very remarkable and almost serpentine form, with four or five fossule, the long dividing septa being present between some of them, but not between others. At one place rejuvenescence occurs in several contiguous calices, and they appear as double, or one within the other, just as they appear in the upper part of Laube’s figure of Elysastrea, and here and there a corallite, near the outside of the corallum, is elevated above the rest and there is a trace of an after- growth of epitheca. HETERASTRHA LATIMHANDROIDEA, Dune. sp. Isastrealatimeandroidea, Duncan, Supp. Brit. Fos. Cor. pt. iv. p. 65, pl. xxv. figs. 18, 19. The specimen of this species, which was obtained by Dr. Wright from the Ammonites planorbis bed of Street, was for some time in my hands, and a facsimile in plaster, taken by means of a wax im- pression, is now before me. Marginal gemmation is obviously very abundant, and the elongated calices having more than one fossula, are indicative of fissiparity. The specimen is only a fragment and its specific independence is very doubtful. HETERASTRHA ? SINEMURIENSIS, From. sp. Isastrea sinemuriensis, E. de From. in Martin, Pal. Strat. de l’Infra Lias, Cote d’Or. Isastre@a sinemuriensis, Duncan, Supp. Brit. Foss. Cor. pt. iv, p. 80, pl. vil. figs. 1-9. If the Brocastle specimens are rightly identified with this species, then it, like so many other of the so-called Isastree of the Lias, increases by marginal instead of calicinal gemmation. This is evident in my specimen, and it has also been figured by Prof. Duncan (Supp. Brit. Foss. Cor. as above) from specimens in the collection of the late Mr. Charles Moore. Of Isastreea gibbosa from the same locality I can only say that in the specimens I have examined there was no evidence of any process of increase. HeErTERASTRMA EXCAVATA, Fromentel, sp. Septastrea excavata, BH. de From. in Martin, Infra Lias, Cote d’Or. 1860. Two specimens of a Coral which I refer to this species have come into my hands, both of which were taken from the low-lying gravel at Charlton, about a mile north-west of Evesham. They resemble each other in having a regularly oval form, and are somewhat depressed, though they have an evenly convex calicular surface. A larger example than either of these would, if broken up, furnish precisely such fragments as the one figured by M. de Fromentel. In all the details of the form, size, and arrangement of the corallites and their calices, as well as the development of the septa, my 216 R. F. Tomes—On Heterastreea, Lower Lias. specimens are fully in accord with the fragment figured by M. de Fromentel, excepting that in addition to fissiparity there is undoubted marginal gemmation, which is, however, unfrequent, not more than three or four instances appearing on either specimen. Hursrastr#A Erurripgst, sp. nov. Pl. VII. Figs. 1, 2. This species, which appears to be undescribed, bears a little resem- blance in the form of the corallum to H. Haimei, but it differs greatly in the size of the calices, which are scarcely half the size of those of the last-named species. The corallum is tall and somewhat compressed, swith a rounded top, the whole surface being closely covered with calices, which are hexagonal, shallow, and saucer-shaped. The walls are thick, but when entire come to a sharp well-defined edge, and there is a very distinct though fine line where the corallites come together, indicat- ing imperfect union. No cyclical numeration of the septa can be formulated. There are about twenty-four in a medium-sized and regular calice, and nearly half of them pass almost into the centre of the calice, but do not quite meet. In the elongated calices, however, the longest from the opposite sides meet in the middle line. The others are too irregular to be determined. All the septa are of medium thickness, which they maintain as they pass inwards. In an unworn calice they all have margins which are regularly tuberculated, about eight to ten prominent tubercles being observable on the longer ones. The tallest specimen I have seen measures four inches in height, and has a diameter of about two inches. Diameter of the calices from one and a half to two lines. Gemmation and fissiparity occur quite freely and with about equal frequency on all parts of the corallum. I have examined several specimens from the Lower Lias of the Hast Cliff, Lyme Regis, and I possess one which was taken from the gravel-pit at Charlton, near Evesham. HETERASTRHA REGULARIS, sp. nov. Pl. VII. Fig. 7. The corallum of all the specimens I have seen was attached by a small oblong space, from which it expanded rapidly, and was sur- mounted by an irregular overhanging flattened or rounded top, with some elevated lines and gibbosities. The corallites are rather small and angular, and, generally speaking, hexagonal, and their union with each other is indicated by a fine but very distinct line. The calices are deep, almost as deep as wide, and. the walls are regular, thin, upright, and straight between the angles. The septa are rather regular, straight, and rather thick, and they hold their thickness quite into the centre of the calice. There are six systems, and three cycles and a rudimentary fourth. The septal edges have large rounded denticulations, which are few in number and lobular. The primary septa are six, and they unite in the centre of the calice and form a false columella, which, however, is not very apparent until the tabulz forming the floor of the calice have been broken through. R. F. Tomes—On Heterastrea, Lower Lias. 217 Those of the second cycle are two-thirds the length of the first, and those of the third two-thirds the length of those of the second, while the septa of the fourth cycle are merely rudimentary. Marginal gemmation and fissiparity both occur, but are not frequent. This species may be readily distinguished from all the others by the small number and the regularity of the septa, the cycles of which can readily be determined in a fairly symmetrical calice. In the larger and more irregular ones, however, the septa are a little more numerous, and the cycles cannot be traced. Another dis- tinction consists in the union of the primary septa low down below the calice, and thus forming a false columella, which becomes conspicuous when the dissepimental floor of the calice has been destroyed and the septa worn down. I have not seen this in any other species. . The most regular calices have a diameter of about two lines, but the larger and more irregular ones are nearly three lines in breadth. Two examples have been obtained from the Ammonites angulatus beds in a field called ‘‘Salmon’s Stile,” near the village of Littleton, north-east of Evesham, and another from near the village of Cropthorne, west of Evesham. HeErerasTR@A BINTONENSIS, Sp. nov. There is a large and nearly globular species having a very gibbous upper surface, and rather small calices with thick walls, which I have at present been unable to refer to any known species. It occurs in the Ammonites angulatus beds at Binton Hill, four miles west of Stratford-on-Avon, and at Down Hatherley, Gloucester- shire, where my friend Mr. Brodie found a specimen, and kindly forwarded it to me for my use on the present occasion. Other specimens have been taken from the Charlton gravel-pit. The calices are rather small, and are mostly hexagonal, but they have a rounded appearance, owing to the walls being thickened just at the angles. They are very seldom elongated. The septa are straight, thin, and in the larger calices there are from forty to forty- six. About nine or ten are longer than the others, but do not meet in the centre of the calice, there being an open fossula of nearly one-fourth of the diameter of the corallite, which is only closed by the tabular dissepiments. A corresponding number of septa are about half or two-thirds the length of the long ones, and all the others are too short and variable to be enumerated. Gemmation occurs rather freely, but fissiparity is much less common. The diameter of a large specimen is about six inches, of a smaller one three or four inches. The calices are from two to two and a half lines wide. The thick walls, the more or less rounded form of the calices, and the open fossula will distinguish this species, and I may add that all the specimens I have seen have had a more or less globular form. HETERASTRHA Sp. I have. before me several specimens of a species which is 218 J. E, Marr—Some Effects of Pressure. obviously quite distinct from any of the foregoing, but which are not sufficiently well preserved to admit of description. They consist of thin plates, from half to three-fourths of an inch in thickness, which had nearly an upright position, and have calices, all of which are oblique. ‘They were found in the neighbourhood of Evesham. DESCRIPTION OF PLATE VII. Fie. 1. Heterastrea Etheridgei, a horizontal section a little below the calice, show- ing the imperfect union of the corallites, fissiparity in pro- gress in two corallites, and one corallite which has resulted from gemmation. Magnified three diameters. BH ee Ep Etheridgei, a vertical section showing the dissepiments and the edges of the septa. Magnified three diameters. 59. Be ae Eveshami, a portion of the type specimen showing a calice which has been developed from a bud, and still retains a more or less circular outline. Magnified two diameters. ae ee 90 Fromenteli, a portion of the specimen figured by Prof. Duncan, exhibiting, in close proximity, both gemmation and fissi- parity. Magnified two diameters. pp) | B09 B55 Tomesi, portions having calices resulting from both gemmation and fissiparous division. Magnified two diameters. POMC si9 regularis, some calices magnified two diameters. 59. be 36 Stricklandi, some calices of a specimen from Evesham, having both gemmation and fissiparous division. Magnified two diameters. pp oe 30 endothecata, a portion of the type specimen, showing fissiparous division in progress. Magnified two diameters. IJJ.—On Somes Errects or Pressur& ON THE DEVONIAN SEDIMENTARY Rocks or Nortu Devon.! By J. E. Marr, M.A., F.G.S. URING Professor Hughes’ annual geological excursion, which was last Easter conducted to Ilfracombe, I was much struck with certain structures exhibited by the ordinary Devonian sediments, and some of these are, I think, worthy of a short notice. Most of them are exhibited on the beach close to Ilfracombe, at the bath- ing place, where there is also seen the folded grit band rendered classical through Dr. Sorby’s writings. ; The rocks here consist of cleaved argillaceous deposits interstrati- fied with thin grits and limestones, and the latter have been folded amongst the former in a most remarkable manner. The changes which take place are illustrated in Fig. 1. The first stage is the production of a series of sigmoidal folds having the middle limb replaced by a thrust-plane. This is well shown in the case of two limestone bands just above a small cave on the shore, at the bathing place. A further development is shown in Fig. la, and the result of this is the formation of a series of ‘“‘eyes”’ of limestone, which vary in length from a fraction of an inch to several feet, according to the magnitude of the folds. As the smaller folds are merely the con- voluted portions of larger ones, the “eyes” get pulled out along the thrust-planes, replacing the middle limbs of the larger folds, as shown in Fig. 1b. In this way, the central portions of these larger folds 1 Read at the Manchester Meeting of the British Association. J. EL. Marr—Some Effects of Pressure. 219 present the appearance shown in Fig. 1c, where we find a series of lengthened “eyes,” forming flattened lenticular patches interbanded with the normal cleaved argillaceous material. By these simple changes we have produced a rock having all the mechanical characters of a schist, but consisting of alternating lenticular patches of limestone and clay-slate, and presenting the apparent false- bedding which is also seen in true schists. The apparent dip of the rocks is here entirely fallacious, and is due to the pulling out of the limestone “eyes,” so as to have their longer axes parallel with the general strike of the cleavage planes. In many cases the cores of the larger folds have the “eyes” compressed together to form an irregular nodular mass, in which the separate ‘‘eyes”’ can be some- My yy) THU Fic. 1 1’. Transition from ordinary overfolds to the stage 1a. >, la. As in text. », la la’. Transition from 1a to 1c as produced along the fault plane in 14. », 6 le. As in text. times with difficulty determined, but at other times the lines of demarcation are wholly obliterated. In these masses, the crinoid joints of which the limestones are largely composed are affected in the way described by Dr. Sorby in his Presidential Address to the Geological Society (Q.J.G.S. vol. xxxv. p. 89), and in some cases are seen converted into a number of irregular polygons. Along the planes where the limestone ‘“‘ eyes” have been dragged out, we find that the crinoid stems are separated in a way similar to that fizured by Heim in the case of a Belemnite (Mechanismus der Gebirgsbildung, pl. xv. fig. 6), and the spaces separating the different joints are then filled with crystalline calcite. 220 J. E. Marr—Some Effects of Pressure. The changes occurring in the case of the thin grit bands are generally similar to those described above; but here we find also that the particles are compressed, and there appears to have been a slight mineral rearrangement. The grits are nevertheless easily distinguishable as such even to the naked eye. The rocks at the bathing place are furthermore traversed by quartz veins, some of which were formed before the principal folding of the rocks, and in this case, the veins are affected in the same way as the thin bands of limestone. Fig. 2 shows the foldings of such a quartz vein, as seen close to the Tunnels at the Fie. 2. (CWC bathing place. Here two quartz veins occur parallel with two thin bands of limestone, and are folded like the limestone, showing that the veins were formed along the bedding planes, before the latter were affected by the folding. At this spot, both limestone and folded quartz veins suddenly disappear against a large divisional plane to the right, and a few feet to the right of this plane a series of quartz veins run parallel with the cleavage planes. It is possible that the latter veins were produced by the mechanical rearrangement of the folded veins along the thrust plane of a large fold, but it is not easy to prove this, as in the case of the limestones, and the rectilinear veins may have been formed in their present condition by segregation. Upon a flat surface of rock to the south of this place, quartz veins are seen formed into “eyes,” and these ‘eyes ” in places have been almost certainly dragged out. In such cases we have the incipient formation of a schistose rock composed of alter- nating lenticular masses of argillaceous material, limestone and quartz. . Precisely similar phenomena may be seen at Hagginton Beach and elsewhere, and indeed the whole coast offers excellent examples of the formation of these schistose structures in ordinary sediments, where all the mechanical peculiarities of a true schist are visible, without any great change in the chemical composition of the individual constituents of the rock. At Hagginton Beach a mass of limestone occurs, which has been pulled out so as to form a series of elliptical nodules occurring in the same line. Here we find the junction of limestone “eyes” without any folding of the particular mass of limestone in which the “eyes” occur. A flattening of these “eyes” would cause the formation of lenticular masses of limestone of a similar character to those described as occurring at the bathing place; nevertheless the mode of formation of the “eyes” is quite different in the two cases. Some of the smaller “eyes” seen in a cliff just north of Hagginton Beach are composed of masses of coral. The elliptical shape of the A. Harker—Geology of Mynydd Mawr. 221 “eyes”? does not appear to be due to the original growth of the coral, for the sides of the nodules are seen to consist of sections of the coral. This may be owing to chemical solution of some parts of the limestone, but appeared to me to be caused by the actual shearing off of a portion of the coral. This supposition requires confirmation, and it is probable that a fuller examination of the district will yield the requisite evidence. The structures seen in these North Devon rocks remind one of those described by Dr. Bonney as occurring at Tor Cross in 8. Devon (Q.J.G.S. vol. xl. p. 1). He brings forward proof to show that in that region “there is no valid evidence of a passage from schist to slate.” The occurrence of rocks in North Devon having all the . mechanical structures of true schists, without possessing their peculiar chemical composition, bears out this conclusion. In con- nection with this, it is of interest to notice that whereas in South Devon, where phyllites are found associated with normal schists, the sedimentary rocks are largely penetrated by igneous intrusions, this is not the case in North Devon, where such intrusions are very rare. One mass of quartz felsite, which has been described by Dr. Bonney (Grou. Mac. 1878, p. 207), does occur at Bittadon, and he states that it is ‘‘ affected slightly by cleavage.” It was therefore intruded prior to the last earth-movements of this area. In some parts of the rock there is a parallelism of the alteration products which have been developed along the line of cleavage, but unfortunately the portion of the rock which has undergone the greatest amount of cleavage is so decomposed that no specimen could be obtained sufficiently firm for slicing. The apparent absence of schistosity in this rock can be however accounted for on the supposition that at the place where it is exposed, the mass forms an “eye” which has not undergone any great change. It would be of interest to know if this rock is exposed elsewhere, and if so, under what conditions it is there found. I am indebted to Mr. E. J. Garwood, B.A., F.G.S., for the use of photographs displaying many of the structures which I have described above. IVY.—Nores on tHE GEoLoGY or Mynypp Mawr AND THE NANTLLE VALLEY. By Aurrep Harker, M.A., F.G.S., Fellow of St. John’s College, Cambridge. YNYDD MAWR, about three miles west of Snowdon, is an abrupt rounded hill, 2300 feet high, separating the valleys of Nantlle and Cwellyn. A reference to the maps of the Geo- logical Survey (75 N.E. and N.W.) shows it to be due to an isolated boss of “intrusive hornblende-porphyry ” in the form of a rounded parallelogram, a mile and a half in its longest diagonal. Dr. Hicks* has mapped this patch as Pre-Cambrian, and included it in his Arvonian system; but apart from its position, breaking 1 Q.J.G.S. vol. xxxv. p. 297, 1879. 222 A. Harker—Geology of Mynydd Mawr. through a regular succession of Cambrian (or Ordovician) rocks, an examination of the junction affords convincing proof of its intrusive character. On the northern flanks of the hill the relations are well exhibited, and the induration and extensive mineralogical alteration of the slate in the vicinity of the boss are very marked. It is indeed by no means easy to determine on the ground the precise point where the hardened, semicrystalline slate gives place to the porphyry. The question may, however, be approached on a different line, which indicates a higher, as well as a lower, limit to the age of the intrusion. P.S.—With reference to the discovery of glaucophane in Anglesey, announced by Prof. Blake in the March Number of this Macazinu, it may be noted that the blue amphibole of the Mynydd Mawr rock differs from that mineral in the character of its absorption and pleochroism, as well as in the absence of crystal form and of the peculiar “cross-jointing.” Glaucophane has not, I believe, been recorded from non-metamorphic igneous rocks. Cambrian Faunas of North America, Bull. No. 30, U.S. Geol. Surv. (1886), p. 72. ® Zeitsch. d. deutsch. Geol. Gesellsch. 1886, p. 899. 7 Thus we find one of the latest writers on it, Mr. C. D. Walcott, stating that the presence of spiculz in this species associates it with the Spongiz, close to the family Euretidse of Zittel, and he considers that the spiculze ‘‘in several of the species have been lost in the crystallization of the calcite now forming the skeleton,’’ /.c. p. 80. 228 Dr. G. J. Hinde—Spicules in Archeocyathus. places on their outer surfaces small rounded granules like those of Beekite. The fragments are in part porous, and several of them are filled with fragmentary spicules dispersed irregularly in the rock, and apparently in various stages of dissolution. In the finer débris are smaller particles of silica and detached entire and broken spicules. From these I have picked out fairly complete fusiform acerate spicules (Fig. 1, 6, c, d), acuate or pin-shaped spicules (a), and portions of nearly cylindrical forms (e). The spicules are of chalcedonic silica, and their axial canals are preserved in many instances. They are common types of siliceous monactinellid spicules, and belong to at least four species of sponges. Forms of a similar character, and similarly detached, are very abundant in the cherty beds of the Yoredale rocks of Yorkshire. I have but little doubt that these siliceous fragments from the Mingan strata, in which Archceocyathus occurs, have been produced by the dissolution of the spicules of disintegrated monactinellid sponges, and the redeposition of the silica as Beekite. I have not, however, detected in the débris examined a single fragment of the so-termed ‘branching spicula’ (Fig. 1, f—7), described and figured by Billings as forming part of the substance of the outer wall of A. Minganensis. Judging from the figures given of them, I do not think they can be regarded as spicules; they are merely abruptly broken fragments of what appears to have been a delicate continuous porous membrane; no two of them are similar, and they do not bear any definite resemblance to any sponge spicules with which I am acquainted. I have no doubt that—as stated—they form part of the outer wall of Archeocyathus Minganensis, but instead of being ‘branching spicula,’ they are merely broken portions of the calcareous tissue of the outer wall, replaced by silica. ‘The structure of the outer wall in the allied species A. Whitneyz, Meek, is described? as consisting of minute punctures so closely crowded that the little divisions between them are scarcely equal in breadth to the punctures themselves, and form, as it were, an extremely delicate kind of network, and the so-termed ‘branching spicula’ in A. Minganensis might well be broken-up portions of a network of this character. Therefore as regards the true sponge-spicules associated with A. Minganensis, it is evident there is no other connection between them and this species than the accident of position, and the so- termed branching spicula, which really belong to this fossil, are in all probability mere siliceous replacements of the tissue of its outer wall. ‘Thus in neither case is there any evidence in support of the view that Archeocyathus is allied to siliceous sponges. My know- ledge of this puzzling fossil is insufficient for me to give a competent Opinion as to its real nature; it is fairly certain, however, that its skeleton was originally calcareous, and it is just possible that careful microscopical examination might give a clue to its relations. 1 American Journ. Sci. vol. xlv. p. 62. Notices of Memoirs—R. Lydekker—Eocene Chelonia. 229 NO tan @ in SS (@iet hve VE @ iS: I.—On Two New Forms or Poryopont anp GonorHYNCHID FISHES FRoM THE Hocene or THE Rocky Mountarys. By Prof. H. D. Corr. Mem. Nat. Acad. Sci., vol. iii. pp. 161-165, with double plate. Ts 1883 (Amer. Nat. p. 1152) and again in 1885 (ibid. p. 1090), Prof. Cope briefly noticed a portion of the trunk of a fish from the Eocene of Wyoming, displaying many points of resemblance to the living Acipenseroid Polyodon, but remarkable on account of its possession of distinct scales, not confined to the upper lobe of the tail. The genus and species received the name of Crossopholis mag- nicaudatus, and in the present memoir Prof. Cope adds a detailed description, with figures, making known also a considerable portion of the skull of the fish. In many respects, the cranial bones are very similar to those of Polyodon, but the snout is relatively shorter, and more closely corresponds in form to that of Psephurus. The body is long and slender, with short dorsal and anal fins, remotely situated, and the former commencing slightly in advance of the latter. The scales are numerous, in oblique series, not quite in contact ; and each consists of a small subquadrate disk, with a row of long, sharp, backwardly-directed spines arranged upon the posterior margin. In an individual measuring 0:-170m. from the anterior extremity of the dorsal fin to the notch of the caudal, the scales only measure about one millimetre each way: the caudal fulera are large and strong. Another novelty from the Wyoming shales first noticed by Prof. Cope in 1885 (Amer. Nat. p. 1091) is also figured and described in detail, namely, the Motogoneus osculus. ‘This is of great interest as being scarcely distinguishable from the living Gonorhynchus, except in the dentition; for the latter genus—the only representative of its family previously known —is solely confined to the seas of South Africa, South and Western Australia, and Japan. As well remarked, ‘“‘ The discovery of this type in the Eocene beds of North America is a notable addition to ichthyological science. It is parallel with the occurrence of the family of the Osteoglosside in the same formation, a family also now confined to the Southern Hemisphere.” The memoir concludes with a figure and description of a small Priscacara, supposed to be adult and referable to a new species, P. hypsacauthus; and it is also added that a newly acquired specimen of P. serrata displays massive superior and inferior pha- ryngeal bones, covered with obtuse grinding teeth. Aves Wie I].—Eocrenr Cuenonta From THE Sart Rance. By R. LypeKker, B.A., F.G.S. Paleont. Indica, ser. 10, vol. iv. pp. 59—69, plates xii. and xiii. 1887. WO interesting Chelonian fossils were obtained from the Lower Eocene of Nila, in the Punjab Salt-Range, by Dr. H. Warth, in 1886, and presented by him to the Indian Museum, Calcutta. These form the subject of the present memoir, and are interesting as being the only known Indian Chelonia of earlier date than those 230 Notices of Memoirs—Post- Glacial Deposits of Gotland. of the Siwalik period, with the exception of the small Platemys Leithi from the inter-trappean beds of Bombay. The first specimen described comprises the greater portion of the carapace and plastron of a Pleurodiran Chelonian, characterized by the absence of epidermal shields. In the latter feature it agrees precisely with the genus Carettochelys, recently discovered by Dr. H. P. Ramsay in the Fly River, New Guinea, and may therefore be placed in the family of Carettochelyide, as defined by Boulenger; its generic distinctness, however, is indicated by the neural plates being in contact, not separated by the costals, and also perhaps by the presence of a mesoplastron. ‘The plastron is marked by a pitted sculpture, and the genus and species receives the name of Hemichelys Warthi. he second fossil is much less complete than the first, and is provision- ally referred to a new species of Podocnemis, under the name of P. indica. The greater portion of the carapace is preserved, and its total length would probably be about 35 inches; it is oval, tectiform, not keeled, and narrowed posteriorly. Though now confined to South America, the occurrence of Podocnemis and Platemys, in the Indian Tertiaries, is not an altogether unexpected fact, the former, at least, also being met with in the Lower Eocene of England; and, as Mr. Lydekker remarks, the available evidence now seems to point to the conclusion, that the original habitat of this group of fresh- water Chelonia was in the northern portion of the Old World, whence they have been driven perhaps by the competition of the Emydians. AC ane IiJ.—Om PostGLactaLa AFLAGRINGAR MED AWCYLUS FLUVIATILIS PA Gortanp. Af Henr. Munrun. Ofversight af Kongl. Vetensk.- Akad. Forhandlingar, 1887, No. 10, pp. 719-782. On Post-GuactaL Deposits witH ANCYLUS FLUVIATILIS ON THE IsLE or Gornanp. By Henry Munrae. URING the last three summers the author of this paper has been investigating the Quaternary deposits of the Isle of Gotland, and he has discovered in various localities shore-deposits or raised beaches (Strandvallar) at different elevations up to 150 feet above the present sea-level, which contain the shells of freshwater mollusca exclusively, more particularly of Ancylus fluviatilis and Limnea ovata. These deposits consist of rounded stones, coarse and fine gravels, and intercalated beds of fine sand, they are chiefly re- arranged glacial deposits formed from the limestone of the district. The shells usually occur in the layers of sand. In 24: localities examined, the L. ovata is found in all save one, and the Ancylus in 19, whilst species of Pisidium are present in 10. Other species of less frequent occurrence are Limneea palustris, Plunorbis contortus and marginatus, Valvata cristata and Bythinia tentaculata, with some Ostracoda. The shells are usually well preserved. Some of these raised shelly beaches are situated on the summits of partially or entirely isolated limestone plateaux, where there is not the least ground for supposing the former existence of small Reports and Proceedings—Geological Society of London. 231 freshwater lakes, nor is there any possibility that the shells can have been wasbed into the sea by rivers and then re-deposited in the beaches. The author believes that these-beaches were formed at a time when the Baltic was a freshwater sea containing a molluscan fauna whose principal representatives are the above-named species of Ancylus and Limnea. There are also on the Isle of Gotland raised beaches of marine origin containing Litorina, ete., which are seldom at a higher level than 50 feet, though one has been described by Lindstrém near Wisby, which is 80 feet above the sea-level. The marine raised beaches are, however, at a distinctly lower level than those with freshwater shells, and must have belonged to a later period, when the freshwater fauna had been supplanted by marine forms. Shell-beaches of a similar character and relative position, and con- taining the same freshwater mollusca, have been described by Friedr. Schmidt in Esthonia and on the islands of Osel and Mohn, but this author regards them, in part at least, as river-deposits, although there are no distinct traces of old river-beds in the localities where they occur.! Prof. James Geikie has also referred to these Russian deposits as indicating that the Gulfs of Finland and Bothnia were freshwater seas at the close of the Glacial period. Further discoveries are requisite before it is possible to lay down approximately the limits of the Baltic at the time when these Gotland freshwater beaches were formed, or to ascertain the nature and position of the barrier which dammed its waters 150 feet above their present level; but the author concludes that its northern half at least, together with the Gulfs of Finland and Riga, formed at the time a single freshwater basin. Ge dig Jal III SOuseitsS YNaNmDy 1-25, Cz aso IAN Ke TS - ———__ GEOLOGICAL Society oF Lonpon. I.—March 28, 1888.—W. T. Blanford, LL.D., F.R.S., President, in the Chair.—The following communications were read :— 1. “On some Eroded Agate Pebbles from the Soudan.” By Prof. V. Ball, M.A., F.R.S., F.G.S. The majority of the pebbles in a collection made by Surgeon- Major Greene in the Sondan, and presented by him to the Science and Art Museum in Dublin, are of very similar character to the agate and jasper pebbles derived from the basalts of India. It may be concluded inferentially that they came originally from a region in which basaltic rocks occur to a considerable extent. A certain number of them are eroded in a manner unlike anything noticed in India, though it is probable that similar eroded pebbles will eventually be found there. Throughout India, wherever there is deficient subsoil-drainage or excessive evaporation and limited rainfall, salts are apparent either in supersaturated subsoil-solutions or as crystallizations in 1 Prehistoric Europe, p. 470. 232 Reports and Proceedings— the soil. They are most abundant in basaltic regions, and in a lake occupying a hollow in the basalt in Berar carbonate of soda is deposited in abundance from the water, which becomes super- saturated during the summer. The author commented on the efficacy of such a liquid as a solvent of silica, and noticed the selective action of the agent which had affected the Soudan pebbles and had corroded some layers more than others ; he suggested that while this might be to some extent due to differences in composition, it was more probably owing to differ- ences of nodular constitution. He considered it unnecessary to refer to the action of humic acid, because while the salt to which the solvent action is attributed would be capable of doing such work, and would be probably abundant in the region referred to, we could not expect any great amount of humic acid in the same area. 2. “On the Probable Mode of Transport of the Fragments of Granite and other Rocks which are found imbedded in the Carboni- ferous Limestone of the Neighbourhood of Dublin.” By Prof. V. Ball, M.A., F.R.S., F.G.S. Angular fragments of granite and of schist, quartzite, and vein- quartz, such as might have been derived from the metamorphosed rocks which rest on the granite near Dublin, have been discovered in beds of Carboniferous Limestone, which often contain fragments of fossils, especially Encrinites. They have been previously noticed by Professor Haughton, Mr. H. B. S. Montgomery, Prof. Jukes, and Mr. Croll. While Prof. Jukes refers their transportation to the agency of land-plants, Mr. Croll quotes their occurrence in support of his argument as to the existence of glacial conditions during the Carboniferous period. The author observed that the specimens exhibited none of the indications of the existence of glacial conditions, whether we regard the characters of the boulders or the nature of the rock in which they are imbedded, which contains no such silt as that occurring in the boulder-bed of the Talchir formation. Whilst rejecting the view that they were transported by ice, he pointed out that they need not necessarily have been carried by land-plants, but that they might have been torn from the sea-floor by marine alge, some of which may have had a more buoyant character than those of modern seas. He cited the case of a sandy beach in the neighbourhood of Youghal, which is strewn with limestone fragments, which had been conveyed by seaweeds thrown up after storms from submarine banks. It was suggested that the occurrence of natural fissures in the rocks and cracks produced by concussions from large masses hurled about by the waves might sufficiently explain how the fragments could be freed from the main mass of the reefs under the stress of the waves. 3. “The Upper Eocene, comprising the Barton and Upper Bag- shot Formations.” By J. Starkie Gardner, Esq., F.G.S., and Henry Keeping, Esq., with an Appendix by H. W. Monckton, Esq., F.G.S. The familiar Upper Eocene having been transferred to the Oligo- cene, the remaining uppermost division of the Eocene bears the title Middle. Unless the considerable literature relating to the Brackle- Geological Society of London. 233 sham, the Calcaire Grossier, and the Nummulitic, is to be rendered obsolete, their classification as Middle Hocene must be preserved, and a modified Upper Hocene constructed out of the Barton series. The authors’ proposal is that the following should be adopted :— London Area Hampshire Area. ( Upper Barton. Upper Eocene - Middle ,, \ Upper Bagshot Sands. Lower ,, The base of the formation is not sharply defined, but it coincides with the final disappearance of several subtropical Mollusca, and almost with the extinction of Nummulites in our area. The upper limit is drawn at the base of the Lower Headon, where the brackish fauna gives place to one of fresh water. The conditions of deposition were examined at some length, and evidence in support of the estuarine origin of the formation was adduced. The section in Christchurch Bay was described first, and the thickness and characteristics of each subdivision given, the total reaching 170 to 180 feet. It commences with 45 feet of whitish sand, and, in ascending order, a pebble-bed, 11 feet of greenish clay, and a band of imperfect ironstone underlying the zone of Nummulites elegans. ‘Then 20 feet of stiff drab clay, 13 feet of drab clay with sand-drifts, and 12 feet of the same, known as the Highcliff Sands. The Lower Barton terminates with the Pholadomya-bed. ‘The fauna of this division comprises many Bracklesham species, which range no farther up, and a large number of peculiar species. ‘The most convenient base-line for the Middle Barton is the lowest of several bands of Septaria, which distinguish the 50 feet of drab clays which are comprised in it, and it terminates in a very remarkable formation known as the shell-bed, which, though only a foot or two thick at Highcliff, thickens to about 15 feet to the east, and to 22 feet in the new Christchurch cutting. The finest Barton fossils are obtained from the Middle division ; but though so many splendid species characterize it, few are absolutely confined to it. The upward range of a further number of Bracklesham species ceases at the shell-bed. The Upper Barton includes the Chama-bed, the Becton Bunny and the Long-Mead-End beds. The Becton Bunny beds, 52 feet thick, are sand in the lower half and sandy clay above—Oliva Branderi is the characteristic fossil, and a large number of bivalves and brackish Headon Gasteropods come in. Opinions have differed considerably as to whether these beds should be included in the Bartons. The series closes with the Long-Mead-End Sands, 20 feet thick, with similar fossils, and formerly known as the Upper Bagshot Sands of the Hampshire basin. The section is continued without any break into the Lower Headon. The next section described was that exposed in the cuttings for the new line from Brockenhurst to Christchurch, and here great changes in the relative thicknesses are seen, confirming the view that the Barton formation is the local deposit of a limited estuary. The | Chama-bed remains 18 feet thick, but the shell-bed thickens to 22 feet, and the drab clay with Septaria is only 10 feet. ‘The under- 204 Reports and Proceedings— lying greenish compact clay looks like Lower Barton, but may belong to the Middle. The Upper Bartons are much weathered and un- fossiliferous, but the Paludina-beds of the Lower Headon do not appear for 5900 yards east. Some of these, 2380 yards west of the Brockenhurst road, are violently contorted. The Alum-Bay section was then compared with those previously given, and the authors also noticed the Bracklesham, Stubbington, and Hunting-Bridge sections to show the transitional character of the highest of the Bracklesham beds. The paper concluded with an analysis of the fauna, and carefully revised and tabulated lists. Mr. Monckton, in his Appendix, stated that in the London basin the Barton beds are represented by the Upper Bagshot Sand, a mass of yellow or nearly white sand without clay-beds, though often loamy. Its greatest proved thickness is 2284 feet, and the base is marked by a very persistent bed of pebbles. Its extent is considerably greater than is shown on the Geological Survey map. Casts and impressions of shells are abundant in some places, but recognizable species have only been found at ‘Tunnel Hill near North Camp Station, Aldershot. A large collection from this place has been made by Mr. Herries and by the author. IJ.—April 11, 1888.—W. T. Blanford, LL.D., F.R.S., President, in the Chair.—The following communications were read :— 1. “On the Lower Beds of the Upper Cretaceous Series in Lincolnshire and Yorkshire.” By W. Hill, Esq., F.G.S. The Red Chalk which forms the basement-bed of the Upper Cretaceous in Lincolnshire and Yorkshire is a continuation of the Hunstanton Limestone. Its thickness increases in South Lincoln- shire to thin away again in the north of that county; but it again increases north of the Humber for a while. Near its most north- westerly exposure on the Yorkshire Wolds the red colour is lost; but Inoceramus sulcatus and Belemnites minimus are found in a dirty yellow-coloured material of trifling thickness. Eastwards it regains its red colour and thickness, so as to be upwards of 30 feet at Speeton, where also it is less calcareous. This section was described in detail, and the results compared with those of other writers. The author speculated upon the probable limits of the Upper Cretaceous sea at this period on evidence mainly based upon the amount of matter of inorganic origin. He noted that Am. interruptus has been found at Witheall, Am. rostratus at South Cave, and Am.? auritus at Wharram Grange. The base of the Chalk Marl through Lincolnshire continues to be marked by a bed of compact limestone, which is the representative of the “sponge-bed” of Hunstanton. This can also be traced in Yorkshire as far as the north-western extremity of the Wolds. Above this a few feet of grey gritty chalk retain the character of the “ Inoceramus-bed” throughout the area above mentioned. At the north-western extremity of the Wolds the main mass of the Chalk Marl has diminished in thickness, but more than recovers Geological Society of London. 239 this at Speeton, where, according to the chemical and microscopical evidence, there is a complete passage from the “Gault” to the “Chalk Marl.” The peculiar development of the latter at Speeton was very fully described. No bed such as the Cambridge Greensand or the Chloritic Marl can be taken as a line of separation. Throughout Lincolnshire and Yorkshire certain courses of grey- coloured chalk are recognizable on the horizon of the ‘Totternhoe Stone: these are known collectively as the “Grey bed.” Much comminuted shell and numerous Pectens characterize this bed, which is faintly recognizable even at Speeton. The “Grey bed” deter- mines the upper limit of the Chalk Marl. ‘The equivalents of the Grey Chalk vary less in thickness throughout the area than those already described. Certain lithological characters, which first begin to manifest themselves in the marly beds just above the Totternhoe Stone in Norfolk, become greatly developed in South Lincolnshire, and throughout that county, as in Norfolk, the Grey Chalk is usually of a marly nature. In Lincolnshire there is much red colouration on this horizon. The occurrence of Belemnitella plena in Lincolnshire has been recognized. ‘The band of bluish black clayey material in which it occurs at Barton continues throughout Yorkshire, but no Belemnite has yet been found. Allusion was made to the characteristic features towards the base of the Middle Chalk. Lists of fossils were given, and a new species of Holaster (H. rotundus) was described. Numerous chemical analyses and microscopic details of structure were also given. 2. “On the Cae-Gwyn Cave, North Wales.” By Henry Hicks, M.D., F.R.S., F.G.S., with an Appendix by C. E. De Rance, Esq., F.G.S. The author gave an account of the exploration of the cavern during the latter part of 1885, and during 1886-7. He considered that the results obtained during that time proved conclusively that there was no foundation for the views of those who contended that the drift which covered over the entrance and extended into the cavern was remanié, but they proved that the deposits which lay over the bone-earth were in situ, and were identical with the normal glacial deposits of the area. These deposits had once extended con- tinuously across the valley, and the cavern (400 feet above Ordnance Datum) had consequently been completely buried beneath them. The cave must have been occupied by animals during the formation of the bone-earth, before any of the glacial deposits now found there had accumulated, and a thick floor of stalagmite had covered this “earth” before the cavern had been subjected to water-action. This action had broken up the floor, and completely re-sorted the materials, and added sandy and gravelly material to the deposits ; this sand and gravel had been examined by Prof. Boyd Dawkins, who found that it agreed in every particular with the glacial sand and gravel occurring in the valley a little way above. The large limestone blocks in the cavern had also been evidently disturbed by water-action ; they were invariably found in the lowest deposits, and were covered over by laminated clay, sand, and gravels. The author considered it certain 236 Mr. Correspondence—A. J. Tukes- Browne. that the caverns had been completely filled with these materials, and in the case of the Cae-Gwyn cave they appeared to have been con- veyed mainly through the entrance recently discovered under the drift. The stratification at this entrance was so marked, and could be traced so continuously inwards over the bone-earth, that there could be no doubt that this was the main entrance. There was not the slightest evidence that any portion of the material had been conveyed in through a swallow-hole, and the conditions witnessed throughout were such as to preclude any such idea. The author quoted a Report by Dr. Geikie, who considered that the wall of the cavern had given way, but before the deposition of the glacial deposits, which were subsequently laid down against the limestone bank so as to conceal this entrance to the cavern. In conclusion, he referred to the presence of Reindeer remains in these caves, in conjunction with those of the so-called older Pleisto- cene mammalia, proving that these had reached the area long before the period of submergence, and evidently at an early stage in the Glacial period. It was important to remember that Reindeer remains had been found in the oldest river-gravels in which implements had been discovered. Man, as proved by the implements discovered, was also present at the same time with the Reindeer, and it was therefore natural to suppose that he migrated into this area in company with that animal from some northern source, though this did not preclude the idea that he might also have reached this country from some eastern or southern source, perhaps even at an earlier period. Mr. De Rance, in an Appendix, confirmed Dr. Hicks’s observa- tions as to the identity of the deposits outside the cavern with those in its interior, and noted the occurrence of limestone blocks in the lower deposits, not merely at the spot where the supposed broken wall was situated, but also throughout the whole tunnel. He stated that the sand-bed forming the uppermost cave-deposit resembled the sand associated with gravels in a pit 400 yards east of the cave at a slightly higher level. The drift exposed in this gravel-pit he believed to be of the same age as that of the Mostyn and Bagillt pits to the north, which were undoubtedly overlain by Upper Boulder-clay. The westerly termination of the bone-earth outside the cave had not been determined, which he regretted; but traces of bone had been found at a point five feet from the overhanging ridge of the cave. CORRHSPON DENCE. PALHONTOLOGICAL NOMENCLATURE. Sir,—The questions raised by the gentleman signing himself Rob. W. Haddow in the Grou. Maa. for November, 1887, and discussed by Mr. 8. 8. Buckman in the March number, are well worthy of further consideration in your pages. I confess that I largely agree with Mr. Haddow in his protest against the entire suppression of the old genus Ammonites, and I would reply to Mr. Buckman, (1) that the genera of one family Correspondence—Mr. A. J. Jukes-Browne. 237 should differ from one another in characters of equivalent value, and (2) that it is not necessarily wrong “to include in the same genus species descended for a long time through entirely different lines of ancestors.” There is in fact very little wrong or right in the matter, it is one of convenience and of sensible proportional treatment. We may admit that the whole family Ammonitide requires revision and reconstruction, and possibly that it is desirable to create a certain number of new genera out of the old genus Ammonites, but I join Mr. Haddow in protesting against the infinite subdivision which some paleontologists are trying to force upon us. The old principles of classification may not be defensible, but is it so very certain that some of the principles now adopted in their stead, such as the form of the mouth, are any better? Is there not some analogy between the case of the genus Ammonites and that of the genus Heli, in which an infinity of peculiar variations occur in the shells without any important differences occurring in the structure of the animals ? If mere sections and subgeneric groups are raised to the rank of genera, the old genera become tribes and subtribes, and Mr. Buck- man even wants us to accept names for generic and subgeneric groups, ranking between genera and subtribes. Surely, Sir, such an arrangement as he gives us in his Monograph on Inferior Oolite Ammonites is the height of cumbrousness, and shows the absurdity to which the system is capable of being carried. Stated in full this arrangement is as follows :— Family—Ammonitidee. Subfamily—Ammonites (note the termination). Tribe—Agoceratidee. Subtribe—Harpoceratine. Generic group—Hammatoceratidee. Generic subgroup—Hildoceratinee. Genus— Ludwigia. Species—Murchisone. Really I think a trinomial or even a quadrinomial system is better than this, which is practically a septinomial one. The small section of a group which is here elevated into a genus hardly merits a name at all, it is a mere section of Harpoceras which may be regarded as a subgenus of Ammonites. I therefore take up Mr. Buckman’s challenge, and would speak of the species trinomially thus— Ammonites (Harpoceras) Murchisone, # FA Bs var. obtusa. By this method it would still be possible for the stratigraphical geologist to speak of it as Ammonites Murchisone, while the paleon- tologist who makes a special study of the genus would doubtless usually call it Harpoceras; but no other Ammonite could receive the same specific name, whereas, if Harpoceras be admitted as a generic name, new species referable to that genus might receive the same names as those now applied to other well-known species of Ammonites; thus we might have Harpoceras cordatus, H. cristatus, ete. As regards the rectification of erroneous identifications, we are of 238 Correspondence—Dr. C. Callaway—Prof. Prestwich. course indebted to Messrs. Wright and Buckman for their researches, and if necessary the names of species taken to characterise given zones must be altered in accordance with their determinations. In no department has our nomenclature yet reached perfection, and as Mr. Buckman says, we must effect changes of name as our know- ledge increases, but at the same time we must agree upon general systematic principles. A. J. Juxes-Browne. SHIRLEY, SOUTHAMPTON. GLAUCOPHANE IN ANGLESEY. Sir, —The interesting paper by Prof. Blake, ‘‘On the Occurrence of a Glaucophane-bearing Rock in Anglesey,” which appears in your March issue, suggests a question of nomenclature which is likely to give us some trouble. Jam very glad to have Prof. Blake’s support in assigning ah igneous origin to some of the Anglesey schists ; but now that they are schists I should hesitate to call them ‘joneous.” In Prof. Bonney’s description (quoted by Prof. Blake) of a specimen from the Anglesey column, the constituent minerals are “probably a species of chlorite,’ ‘epidote,” “ quartz (?),” and “mica”; and they form ‘a foliated dense felted mass.” According to my view, in which I understand Prof. Blake to acquiesce, this rock was once a diorite (hornblende and plagioclase). If so, the change from the eruptive ‘rock to the schist is surely entitled to be called a metamorphosis. If we apply the term ‘ igneous” to a crystalline schist when we can assign to it an eruptive origin, must we call it “aqueous” when we know it was once a sediment? And under what head must we class it when its genesis is unknown to us? I grant that in tracing a diorite or a granite into a schist, we cannot fix a hard boundary-line between the two; but a similar difficulty meets us in the study of metamorphosed sediments, and it is not found to be very serious. However, I write rather to raise a question than to settle it. If we are not to call crystalline schists by the term “ metamorphic,” how shall we designate them? They would be as sweet to me by any other name. WELLINGTON, SALOP. Cu. CALLAWAY. THE ATMOSPHERE OF THE COAL-PERIOD. Str,—In the review of the 2nd Vol. of my treatise on Geology which appeared in the last number of your MaGazine, your reviewer remarks (p. 161), “The author considers that, during the Coal-period, the atmosphere was more dense, and more charged with moisture and carbonic acid, and he is led ‘to conclude that the coal-growth was in all probability one of extreme rapidity, and consisted of woods and plants containing a much larger proportion of carbon than any existing forest vegetation.’ With regard to the excess of carbonic acid gas, Mr. Carruthers has expressed an adverse opinion, and experiments made on living plants have shown that they are liable to be poisoned, like animals, by an excess of the gas.” y > £. ’ The hornblende, which is of a rich green colour, is chiefly remarkable for the imperfection of its cleavage-cracks, these being not nearly so sharply defined as is usual in this mineral. Its relation both to the olivine and to the hypersthene shows that the hornblende was the last product of consolidation. It is found, for instance, enclosing grains of both hypersthene and olivine—a structure which, when more largely developed, produces the ‘ lustre- mottling’ described by Williams and others. The pleochroism, which is marked, is as follows :— a=pale yellow. B=yellowish green. y=bluish green. Mh Bore se 1 Thomson (‘¢ Through Massai-Land,’’ London, 1885) repeatedly mentions the occurrence of metamorphic rocks in this neighbourhood. ‘They are seen, according to Dr. F. H, Hatch—A Peridotite from Kilimayaro. 259 The olivine is perfectly fresh and consequently colourless. High magnification discloses, both in this mineral and in the hornblende, the presence of parallel rows of opaque rod-like enclosures. The freshness of the minerals that contain them seems to preclude the idea of these bodies being of secondary origin. The iron-ore occurs in irregular opaque grains which are easily attracted, and removed from the powdered rock, by a small bar-magnet. These grains are often edged by irregular plates of a translucent green mineral, which also occurs in isolated grains, or included in the hypersthene. In the latter case it sometimes assumes an octahedral form. It is isotropic and belongs probably to the spinell-group (pleonast or hercynite). With regard to the name applied to this rock, its right to a place among the peridotites is at once established by its high density (sp. g.=3'3), the complete absence of a felspathic constituent, and the presence of a considerable proportion of olivine; although the latter is not the dominant constituent. Were the classification advocated in the new edition of Rosenbusch’s ‘‘ Physiographie der massigen Gesteine”* to be followed, the rock would have to be referred to the hornblende-picrites. Since, however, it bears no resemblance in structure and composition either to the rocks to which Tschermak originally gave the name picrite, or to those, for which 15 years later Prof. Bonney proposed the name horn- blende-picrite, I do not feel justified in adopting these terms. Indeed no small confusion seems to have been caused, here as in other cases of rock-nomenclature, by the modification in the meaning of a term, the extension of which has been clearly limited by its originator. The name picrite was given by Tschermak,’ in 1866, to crystalline rocks which are intrusive in the limestones and sandstones of the Cretaceous and Eocene formations of the highlands between Neutitschein, Teschen, and Bielitz, in Moravia and Silesia. These rocks “are described as consisting “to the extent of one half of crystals and grains of olivine; further of a lime-felspar, together with diallage, which can be replaced by hornblende, augite or biotite. The texture is porphyritic, with regard to the olivine, or finely granular.” . .. . “ Picrite bears the same relation to olivine-gabbro as basalt or melaphyre to gabbro.”* Like basalt it often possesses ‘an interstitial substance which consists partly of microlites, partly of a structureless isotropic glass.” * Later on we find Giimbel ° applying the term palcopicrite to altered rocks which consisted originally of olivine, pyroxene, and a small this author, to crop out at the very foot of Kilima-njaro on the E. and S. sides. O. Miigge (Neues Jahrb. B.B. iv. 1886, p. 576) has described gneissose mica-schists and amphibolites from the southern portion of Massai-Land, as constituting members of a ‘‘ gneiss or granite-gabbro formation.’’ 1 1887, p. 260. 2 Sitzungsber. K, K. Akad. der Wissensch. Wien, 1866, Bd. liii. p. 260. Sitzungsber. K. K. Akad. der Wissensch. Wien, 1867, Bd. lvi. p. 274. * Die Porphyrgesteine Oesterreichs, etc. Wien, 1869, p. 245. ° Geogn. Beschreib. des Fichtelgebirges, Gotha, 1879, p. 150. 260 Dr. F. H. Hatch—A Peridotite from Kilimayaro. quantity of plagioclase and brown mica. The new word was scarcely wanted ; but still an intelligible use can be made of it, if it be noted that the palzopicrites bear the same relation to the diabases that the picrites do to the basalts. In short the paleopicrites are olivine- diabases in which the felspar is quite subordinate. In this country we have as examples of typical paleopicrites, the Blackburn and Inchcolm rocks, described by Dr. A. Geikie.! In 1881 Prof. Bonney? proposed the subdivision of the picrites into hornblende-picrite and augite-picrite, according as the dominant bisilicate is hornblende or augite. Adopting this subdivision, Rosenbusch, in his new edition, has defined the hornblende-picrites as peridotites which consist essentially of olivine and hornblende, and the picrites as peridotites which consist essentially of olivine and augite, the term peridotite being restricted to “plutonic rocks (Tiefengesteine) with hypidiomorphic-granular structure and charac- terized by the absence of felspar and the presence of abundant olivine.” This, it will be seen, is a considerable change in the meaning originally attached by T'schermak to the term picrite ; and the latter, as defined by Rosenbusch, admits of considerable variation in structure and affinities. On the other hand, Tschermak’s picrites (e.g. that from Giimbelberg near Neutitschein) have been relegated to a new group, viz. that of the “ picrite-porphyrites.” * The conclusion to be drawn from these digressive considerations is that the picrites (or paleopicrites) are olivine-augite rocks which possess affinities with, and pass, by an increase in the amount of felspar, into dolerites (or diabases) and basalts; while the horn- blende-picrites, on the other hand, appear to be rocks which possess affinities with, and pass into, diorites. The peridotite from Kilima-njaro, described above, contains no trace of felspar, has a specific gravity of 3:3, is holocrystalline and granular, and exhibits indications of foliation—characters which are incom- patible with those of the picrite group. It bears, however, some resemblance to the hornblende-peridotites of Peekskill, Hudson River, N.J., described by G. H. Williams ;‘ and I have therefore followed his system of nomenclature. If a distinctive name were really requisite, the name Cortlandtite, suggested by Williams for these rocks because of their relation to the Cortlandt series of Dana, might be adopted. Mr. Teall has shown me peridotites from Scourie in Sutherland- shire, which bear a still more striking likeness to the Kilima-njaro rock.° 1 Trans. Roy. Soc. Edin. vol. xxix. (1880), p. 504. 2 Q. J. G. 8S. vol. xxxvii. (1881), p. 137. 3 Physiog. der Massig. Gest. 1887, p. 518. * Amer. Journ. of Sci. vol. xxxi. 1886, p..26. y ae Scourie rocks are placed by Rosenbusch among the hornblende-picrites, l.c. p. 267. Louis Dollo—On the Humerus of Euclastes. 261 V.—On tHe Humerus or HuctrasTes. By Louis Dotto, C.E.; Assistant Naturalist in the Royal Museum of Natural History of Belgium, Brussels. I.—To avoid useless repetitions, I shall consider as admitted what I have said in my paper “ Sur le genre Euclastes,”’! especially : 1. Huclastes, Cope = Chelone, Owen (non Ritg.) (pars) = Lytoloma, Cope = Puppigerus, Cope (pars) = Glossochelys, Seeley = Pachy- rhynchus, Dollo = Erquelinnesia, Dollo. 2. The diagnosis of the Propleuride, as 1 have completed it. II.—This being stated, I think that the far more chelydroid than chelonoid humerus of the above-named Turtles is one of the most interesting facts of their organization. Indeed, if we remove, for the present, from the Dactyloplastrine Cryptodiran Thecophorian Chelonians : ? 1. The Trionychide, with which the Propleuride have nothing in common, as is sufficiently proved particularly by their carapace and their plastron ; 2. The Propleuride themselves, since it is precisely these which we are comparing with the others; we have only really to examine the two following types: 1. The Chelonide ; 2. The Chelydridea. Now, by their skull® and their proccelous caudal vertebre,‘ the Propleuride are related to the first-named family. Their carapace and their plastron would, it is true, appear to place them nearly at an equal distance between the Ohelonide and the Chelydride, especially on account of the degree of ossification. Nevertheless, as the nuchal bone does not possess the characteristic costiform process of the latter,> I think that we should not be justified in regarding the structure of the carapace and plastron as a sign of relationship with the last-mentioned family ; it is a question, in the case which we are considering, of a simple coincidence in two parallel series. The Propleuride might then be looked upon as aberrant Chelonide, ranking 1 L. Dollo, ‘‘ Sur le genre Euclastes,’’ Société géologique du Nord, Annales xy. 1887-88 (in the press). * L. Dollo, “ Premiére Note sur les Chéloniens du Bruxellien (Eocéne moyen) de la Belgique,’ Bull. Mus. Roy. Hist. Nat. Belg., t. iv. 1886, p. 84. 3 R. Owen and T. Bell, ‘‘ Monograph on the Fossil Reptilia of the London Clay,” part i. Chelonia, Paleontographical Society, 1849, pp. 9 and 10; E. D. Cope, “* Synopsis of the Extinct Batrachia, Reptilia and Aves of North America,” Trans. Amer. Phil. Soc. Philadelphia, 1871, vol. xiv. p. 148; L. Riitimeyer, ‘‘ Ueber den Bau von Schale und Schadel bei lebenden und fossilen Schildkréten als Beitrag zu einer palaontologischen Geschichte dieser Thiergruppe,’’ Verhandl. d. naturforsch. Gesellschaft in Basel, vol. vi. 1874-78, p. 122. 4 L. Dollo, ‘* Hueclastes,” etc. (Joc. cit.). It is known that, in the Chelydride, the caudal vertebree are opisthoccelous (E. D. Cope, ‘‘ The Vertebrata of the Tertiary Formations of the West,’’ Rep. U.S. Geol. Surv. Territ. (F. V. Hayden), 1884, p. 111). ° G. Baur, ‘* Osteologische Notizen iiber Reptilien,” Zoologischer Anzeiger, 22 Novembre, 1886, p. 688; R. Lydekker and G. A. Boulenger, ‘‘ Notes on Chelonia from the Purbeck, Wealden, and London Clay,’’ GrotocicaL Macazinz, June, 1887, p. 273; L. Dollo, ‘‘ Premiére Note sur les Chéloniens oligocénes et néogénes de la Belgique,’’ Bull. Mus. Roy. Hist. Nat. Belg. t. v. 1888, p. 92. 262 Louis Dollo—On the Humerus of Euclastes. as a subfamily, my Pachyrhynchyna@,' did not their peculiar humerus show us a type having limbs wholly different from those of the Chelonide, and even to such a degree that, on account of them, it is necessary to create a distinct family, the Propleuride of Mr. KH. D. Cope.” III.—We will now proceed, more in detail, to the study of the humerus in question : 1. To show, first, that it is really more chelydroid than chelonoid ; 2. Then, as it might be doubted, we shall demonstrate that it really belongs to the Turtle to which we ascribe it ; 3. Lastly, we shall draw from our observations the conclusions to which we shall be led, notably with regard to Phylogeny. IV.—To begin with, we shall compare the humerus of Chelydra to that of Chelone; we shall find :* CHARACTERS. CHELYDRA (Fig. 1). CHELONE (Fig. 3). 7 Elongated, sigmoid. Section, at | Less elongated, rectilinear. Sec- Generaltcorm the narrowest point, distally to tion, at the narrowest point, dis- i processes, elliptic, but differing tally to the process, more or less slightly from a circle. elliptic, but very flattened. Heed Longest axis very oblique on the | Longest axis perpendicular to the PEIN longest axis of the distal end. longest axis of the distal end. (g:) HR Hardly rising above the head, whez | Rising very much above the head, Mesial process. the longest axis of the humerus when the longest axis of the (z.) zs vertical, humerus is vertical. ce Clearly detached fi e y detached from the head and Lateral process. | Placed close to the head. placed nearer to the distal end. (2.) Placed close to the head, with the | Less well circumscribed, oblique, 5. longest axis perpendicular to the with the greatest axis nearly direc- Intertubercular longitudinal axis of the humerus, ted according to the longitudinal fossa. and wedged in between the lateral axis of the humerus, extending and mesial processes. towards the distal end. 6. Well marked, and forming nearly | Forming hardly half the distal end Caos the whole of the distal end of the of the humerus; displaced me- a, 6.) humerus. sially. awe Much more developed; i ped; it causes the Bice ak Hardly developed. condyles to be displaced mesially. Teetic nd lar Present, but placed nearer to the eae Missing ; replaced by a groove. longitudinal axis of the humerus (e.) i than the groove of Cheljdra. V.— But: 1. By its general form ; 2. By its head ; 3. By its mesial process ; (Fig. 2.) 4, By its lateral process ; 5. By its intertubercular fossa ; 1 L. Dollo, ‘‘ Premiére Note sur les Chéloniens landéniens (Eocéne inférieur) de la Belgique,” Bull. Mus. Roy. Hist. Nat. Belg. t. iv. 1886, p. 139. 2 KE. D. Cope, ‘‘ Synopsis,” ete., p. 235. 3 L. Dollo, ‘‘ Chéloniens oligocénes,”’ etc., p. 78. Louis Dollo—On the Humerus of Euclastes. 263 the humerus of Huclastes is of the type of that of Chelydra and not of that of Chelone. VI.—Nevertheless, we shall remark that, although being more chelydroid than chelonoid as a whole, the humerus of Huclastes ; 1. By its curvature less sigmoid and its flatter form ; 2. By its head slightly less oblique on the greatest axis of the distal end ; 3. By its lateral process less elevated, slightly more detached from the head, and less distinctly perpendicular to the surface on which the orifice of the ectepicondylar foramen is situated ; 4. By its condyles less developed and slightly more displaced mesially ; 5. By its more marked ectepicondyle ; 6. By the presence of an ectepicondylar foramen ; differs slightly from the type of Chelydra and shows an approxima- tion towards Chelone. The foregoing considerations prove, evidently, that, if the limbs of Euclastes were infinitely less adapted to aquatic life than those of Chelone, they were, however, more so than those of Chelydra and perhaps even than those of Trionyx.1 But we shall return to this subject further on. VIl.—Does the humerus referred to Euclastes Gosseleti, Dollo, belong really to that Turtle? I think so; because: 1. The fossil Vertebrates of the Erquelinnes sandpits were sent to the Museum of Brussels in separate parcels containing bones im- bedded in sand. Tach parcel included the remains of one specimen. Now, we have got two humeri appertaining to the same side (there- fore from distinct individuals), and each of them came in its own parcel containing exclusively bones of Huclastes; I shall also add that they were sent at different times ; 2. The humeri agree in size with the accompanying skeletons ; 3. They are also in the same state of fossilization, they have the same aspect ; 4. If they should not be admitted to belong to Euclastes, taking into consideration the Chelonian fauna of Erquelinnes, there would only remain to look upon them as Trionyx ; but: ; A. They are of too large a size to have appertained to the skeletons of Trionyx of which carapaces have as yet been found at Erquelinnes ; B. They are also too dark in colour ; C. They offer besides differences from Triony« in the general form, the head, the lateral process, the intertubercular fossa, the condyles, the ectepicondyle, and the presence of an ectepicondylar foramen ; 5. Moreover, Huclastes is so abundant at Erquelinnes compara- tively with other Chelonians (certainly 10 to 1 with respect to Trionyx) that: A. If the humeri had been found isolated, which is not the case ; 1 On account of the distal extremity of the humerus, and the metapodials (or phalanges) which seem devoid of condyles, as has already been observed by Mr. E. D. Cope (Lertiary Vertebrata, etc., p. 111), and as I have also noticed (L. Dollo, Euclastes, etc., loc. cit.). 264 Louis Dollo—On the Humerus of Euclastes. B. If their size corresponded equally with that both of Trionya and of Huclastes, which is not the case; C. If the fossilization, and especially the colour, had been the same, which they are not; they ought still, according to the law of probability, to be referred to Huclastes ; 6. Lastly, on the other side of the Atlantic, Mr. KE. D. Cope has made known, a long time ago,! that the Cretaceous Proplewride had a more chelydroid than chelonoid humerus, and he was so much impressed by this structure, amongst others, that he began by placing with the Chelydride the genera which have since composed his Propleuride. After what has been said above, it seems to me beyond doubt that the humeri described as belonging to Euclastes really appertain to that genus. However, a further verification, which I am going to mention, appears to me possible. The Erquelinnes Chelonians are imbedded in sand, consequently in a matrix devoid of cohesion; on the con- trary, the London Clay Chelonians, several of which ought certainly to be classed among the Propleurid@,? are found not only in clay, a more coherent substance, but each of them is said to be included in a “nodule of petrified clay.” ? Under these conditions, the latter show with more certitude the bones which come from the same individual. Now, Chelone longiceps,t Owen, is one of the types belonging to the Propleuride, as I understand them, and the skull, the carapace, as also the humerus, are still adhering together.’ If, then, the humerus is of the shape of our Fig. 2 (Huclastes Gosselett, Dollo), the above-mentioned verification will be made. Therefore, it is to be wished that an English naturalist should consent to examine this point; and it is precisely to make known this desidera- tum that I have chosen the pages of the GrotogicaL MaGazine to publish the present paper. I am aware that Sir R. Owen says, speaking of the humerus in question: “The humerus presents the usual characters of that of the Chelones.”® But the celebrated naturalist may not have had his attention especially drawn to this bone ; moreover, judging by the figure which he gives of it,’ it appears to me somewhat mutilated, as also imperfectly cleared of its matrix. I shall add that it is not one specimen only that should be studied, but all those coming from the London Clay, which can be referred to Propleuride, and in which the humerus is associated, beyond a doubt, with other characteristic remains. VUI.—It ought to be inferred from the preceding pages that the Propieuride were Turtles not so well adapted to an aquatic life as 1 E. D. Cope, ‘‘ Synopsis,” ete., pp. 180 et 235. 2 L. Dollo, ‘‘Chéloniens landéniens,’’ etc., p. 137; R. Lydekker and G. A. Boulenger, ‘‘ Notes on Chelonia,’’ etc., Grou. Mac. p. 271. 5 R. Owen and T. Bell, ‘‘ Monograph,” ete., p. 40. 4 R. Owen and T. Bell, ‘‘Monograph,”’ etc., p. 16. > R. Owen and T. Bell, ‘‘ Monograph,” ete., pl. iv. 6 R. Owen and T. Bell, ‘ Monograph,” etc., p. 17. 7 R. Owen and T. Bell, ‘‘ Monograph,”’ etc., pl. iv. Louis Dollo—On the Humerus of Euclastes. 265 true Chelone, Since the first Chelonians were certainly terrestrial,’ and that the Propleuride are, especially as far as the limbs are concerned, nearer to the primitive stock of the Testudinata than the living Chelone, it may be inquired whether these Propleuride are not the direct ancestors of the latter. I do not think so, for the following reasons. Notwithstanding that the Cretaceous beds * con- taining Propleuride are, without doubt, older than the Cretaceous beds? in which the oldest true Chelone* has been found, and that, consequently, in the present state of knowledge, there is no contra- diction so far, as to time, I am of opinion that the structure of the mandible ® suffices alone to make us consider that descent as impos- sible. Indeed, a short symphysis is primitive, a long one derived. Therefore, it is not at all likely that the latter has given rise to the former. Moreover, the carapace, the plastron, and the choanes ® point also in the same direction.’ IX.—But, without being the direct ancestors of the Chelonide, the Propleuride may enlighten us as to these ancestors, just as Hesperor- nis,* which, on account of its much reduced wings, could not be the precursor of any of the living Birds, throws light on the dentition of the forms from which they have been derived. The Propleuride show us the large head,’ the separated nasals,’? and the more terrestrial limbs possessed at one time by true Chelone. Thus, Paleontology furnishes material proof of facts already foreseen by Morphology. X.—According to Mr. E. D. Cope," the relations between the Dactyloplastrine Cryptodiran Thecophorian Chelonians are the fol- lowing : Chelydrida. Propleurida. ia Trionychida. I cannot admit this grouping, because : 1. How could the Trionychide have transmitted to the Propleuride the marginal bones, which they have lost themselves ? 1 G. Baur, ‘‘ Notizen,”’ etc., p. 688. 2 L. Dollo, “ Euclastes,’ etc. Because, in England, there is no Danian (A. Geikie, ‘‘Text-Book of Geology,”’ p. 815) ; and, in the United States of America, the fossils found in the Fwclastes-beds, for instance, Teredo tibialis and Gryphea vomer, are considered by D’Orbigny as Senonians (Prodrome de Paléontologie strati- graphique, Paris, 1850-52). 3 Danian (Tuffeau de Maestricht). 4°“ Chelone Hoffmanni,’ Gray. . . . ‘ Bis jetzt ist dies indessen das alteste Fossil aus Europa, das mit vollem Recht den Namen Chelone tragt’’ (L. Riitimeyer, “¢ Ueber den Bau,” ete., p. 119). 5 L. Dollo, ‘‘ Chéloniens landéniens,” ete., p. 134. 6 L. Dollo, ‘‘ Chéloniens landéniens,”’ ete., p. 133. 7 L. Dollo, ‘‘ Euelastes,’’ ete. (loc. cit.). 8 0. C. Marsh, “ Odontornithes; a Monograph on the Extinct Toothed Birds of North America,” New Haven, 1880, p. 62. 9 L. Rutimeyer, ‘‘ Ueber den Bau,”’ etc., p. 122. 10 L. Dollo, ‘‘ Chéloniens landéniens,”’ ete., p. 132. 1K. D. Cope, ‘‘ Tertiary Vertebrata,” etc., p. 115. “SSQVOTG [VISOUL “2 . SSIDOIA [V1OyV] “Y -Sntoulng 9yz Jo prey ‘4 { oao0a8 xep{puoordeyoe 10 ‘uaurer0y rep{puoordoyoe ‘a { ap{puoordayoa ‘p ‘e[Apuoo0qoe ‘g $ afApuoooyua ‘v auojayg Jo snriswN~T—"e ‘oI *[souutponbag Jo (sund ‘auo00g JaMOT) UsluspuvT taMoT] OT[OG ‘2/2/2880 sazsnjong Jo snisewNny—'Z ‘O17 ‘oiphyayg) Jo sn1eUMA—"T “OL ’ ‘SHLSVIONA JO SQYYNNH WAHL NO—OTTIOR SInoTt “NW Alfred Harker—On some Anglesey Dykes (No. IIL.) 267 2. How have the proccelous caudal vertebra of the Propleuride become the opisthoccelous caudal vertebra of the Chelydride? Could they have turned themselves the other way? How could the nuchal rib, lost by the Propleuride,! be present in their descendants, the Chelydrida ? 3. Whichever might have been the origin of the Chelonide,’ their relations with the Propleuride do not seem to allow of a diphyletic phylogenetic tree for. these two families. XI.—Therefore, we should more likely have: Chelonide. Propleuride. Trionychide. Chelydride. so. _————————— —— DACTYLOPLASTRINE CRYPTODIRAN T'HECOPHORIAN CHELONIANS. XIJ.—One more word before concluding. The Propleuride not being true Turtles, were they pelagic in their habits? The marine nature*® of the deposit proves nothing in this case, the beds in question containing also Trionyxz, which, as is well known, lives in rivers. The humerus of the Propleuwride has already shown us that the limbs of these Chelonians were less well adapted to aquatic life than those of the true Turtles, but that they were more so than those of Chelydra, or even than those of Trionyx. The metapodials point also in the same direction. As is equally demonstrated by the carapace and diet,* Huclastes was, therefore, probably a very littoral marine type. VI.—Woopwarpi1an Musrum Norrs: on sommz ANGLESEY DYKES. ‘ No. III. By AtrreD Harker, M.A., F.G.S., Fellow of St. John’s College, Cambridge. jie the first paper of ‘this series® were described several dykes from the shores of the Menai Straits, belonging apparently to one system of intrusions, and some of them cutting Carboniferous strata. Their precise age, however, can be fixed only on the suppo- sition that they may fairly be correlated with certain post-Carboni- ferous but pre-Permian dykes in the Anglesey Coal-field. These latter rocks have a strong general resemblance to the Menai Straits dykes, and as they are by no means easily accessible, they will not be described in detail. Only one will be selected, as offering a 1 L. Dollo, “ Huclastes,” ete. (loc. cit.). 2 « On the Relations between Athece and Thecophora,” see L. Dollo, “ Chéloniens oligocénes,’’ etc., p. 83. 3 A. Rutot, “Sur la position stratigraphique des restes de Mammiféres recueillis dans les couches de 1’Eocéne de Belgique,’ Bull. Acad. Roy. Belg. 1881, t. i. p. 22. 4 L. Dollo, ‘‘ Chéloniens landéniens,”’ etc., p. 188. _° Grou. Mac. Dec, III. Vol. IV. p. 409, 1887. See also op. cit. p. 546. 268 Alfred Harker—On some Anglesey Dykes (No. III.) rather pronounced type: the specimen is from the Henslow collection. [571.] Dolerite from dyke in coal-pit at Llanfihangel. This rock is very fresh and of rather coarse grain: it shows at a glance a tendency to parallelism in the felspars. Magnetite is abundant in the slide, partly in square sections earlier than any other constituent, partly in granular and imperfectly crystalline patches later than the dominant felspar, but included in the augite. The felspars divide into two distinct generations. The earlier ones occur in well-formed crystals, of elongated rectangular section up to O-1 inch in length, with a fine distinct twin-lamellation. These lamelle, sometimes interrupted or discontinuous, correspond to the albite law, but they are often crossed by pericline twinning, and some of the larger crystals exhibit the Carlsbad type also. These earlier felspars have little or no zoning, and seem to be andesine or labradorite. They are, however, not strictly all of one stage, for we may see one crystal moulding another, which in turn encloses a small felspar of still earlier consolidation. The later generation of felspars differs considerably from the former. The crystals are less elongated and usually shapeless. They are less finely twinned, and the lamellation is rendered indis- tinct by the strong zonary banding which is made manifest between crossed Nicols. In all these Anglesey dolerites this growth in con- centric zones of different optical characters is highly characteristic of the later felspars. It points to a rather rapid change in the chemical constitution of the magma during the closing stages of consolidation, and perhaps depends partly on the almost simultaneous separation of the augite. In the present rock the augite is not very abundant, and does not build ophitic plates of any great extent. It rarely presents imper- fect crystal boundaries to the later felspars, and is on the whole nearly contemporaneous with them. The mineral is pale brown, with the usual prismatic cleavage. It will be observed that the Llanfihangel rock compares closely with those from the Straits, such, for example, as the Cadnant dyke [545]. Before proceeding further, it may be noticed that there are other dykes in southern Anglesey, which are probably not to be grouped with the foregoing. They differ from them both mineralogically and structurally, and approach more nearly to the characters of parts of the Holyhead dykes to be described below. Asan example, a dyke at Bodowen, on the west side of the Malldraeth estuary, is chosen. [598.] Olivine-diabase of Bodowen. This is an ophitic rock with but one set of felspars. Under a low objective we see first skeletons of ilmenite, clouded with semi-opaque leucoxene, and some crystals of magnetite. There are also numerous rounded light-green patches, in part serpentine, in which are imbedded granules of unaltered olivine. These patches, often included in the augite, are crowded with minute matted fibres, perhaps chrysotile, but more probably Alfred Harker— On some Anglesey Dykes (No. III.) 269 tremolite. Felspar crystals are plentiful, mostly once twinned and with moderately wide extinction-angles in sections perpendicular to the twin-plane. They are moulded and enclosed by large ophitic plates of augite with the characters usually found in that mineral in the Welsh diabases. The edges of these plates are touched here and there with brown hornblende, with the regular crystallographic relations to the augite, and possibly derived from it. Where ser- pentinous pseudomorphs are included in the augite, there is often a fringe of pale green or colourless amphibole, with a definite crystal orientation projecting into the serpentinous mass. This mineral is no doubt a “secondary enlargement’’’ of the augite crystal from which it grows, though its substance must be derived from the destruction of the olivine. Holyhead main dyke-—We now pass on to the island of Holyhead, where two large dykes were first noted and described by Henslow. The main one, with an average width of 60 feet, traverses almost the whole length of the island, running in a slightly curved line, but with an average bearing north-west and south-east, from near the South Stack to Cymmeran Bay. It cuts the quartz-rock, the green schists, and the serpentine, occasionally throwing off veins or branches. Henslow carefully notices the contact-alteration of the adjacent rocks, and makes the observation that “where the dyke is contained between parallel walls of the schist, and appears as though it were filling up some large crevice, the effects are never so striking as in those places where it ramifies and becomes intimately associated with the surrounding mass.”* He also remarks the variability of character displayed in this and the following dyke when traced along their length, a feature still more clearly brought out by an examination of slices under the microscope. [605.] Olivine-diabase from Porth-dafarch (Port Dafreth of Hens- low). ‘The name diabase is employed for this rock, despite a certain approach to the doleritic type, shown by a tendency to develope a second generation of felspars: the structure is ophitic. Olivine grains are abundant and tolerably fresh: they are sometimes slightly penetrated by the felspars. A few imperfect crystals of magnetite are included by the olivine, but the bulk of the mineral is posterior to the dominant felspar. The felspar, apparently labradorite, shows cross-twinning and some zonary shading in polarised light. A few rather shapeless crystals, with strong zoning and less pronounced twin-lamellation, belong to a rather later stage. Pale-brown augite forms large ophitic plates including olivine and felspars alike. The plates are divided by definite lines into distinct fields, with crystal- line continuity, but slightly different optical properties, and this structure sometimes approaches the regularity of the well-known ‘“‘hour-glass augite.”’ [614.] Dolerite from a small branch of the dyke at the same locality. This rock presents no special peculiarities: if olivine has been present, it is now lost in ill-defined secondary products. The 1 Gf. Van Hise, Amer. Journ. Sci. (3) xxiii. p. 385, 1887. * Trans. Camb. Phil. Soc, vol. i. p. 419, 1822. 270 Alfred Harker—On some Anglesey Dykes (No. IIT.) structure is distinctly porphyritic as regards the felspars; there is a rather fine-grained ground of ophitic appearance. [617.] Specimen from the southern part of the dyke, showing the junction of two different rocks. The coarser-grained one is seen under the microscope ta be a diabase, partly ophitic, partly granulitic in structure: no evidence of olivine is to be detected. The finer-grained rock has a ground-mass of minute felspar- microlites and crystals of magnetite, moulded by augite. In this ground are imbedded felspars of rectangular section and a few idiomorphic augites. This rock, which may be styled an augite- andesite, is doubtless a small dyke intruded into the diabase, for it shows a marked fluxional appearance along the line of junction. Cordier compared specimens from this main dyke of Holyhead Island with the “ granitoidal ophites of the Vosges.” Holyhead Eastern dyke.—The second large dyke in the island probably branches off at an acute angle from the main dyke about the middle of its length, and runs in a direction N.W. by N. past the east side of Holyhead Mountain, passing out to sea at the north end with a thickness of 80 feet. Our specimens are from the northern extremity, from Cae Seri on the road to South Stack, and from Bryniau Geirwen on the road to Porth-dafarch. They vary in grain and in general appearance to the eye, some resembling gabbro and others diabase and dolerite. Their intimate structure reveals corresponding variations, but it is perhaps best to class them all together as hornblende-diabases of various types. Under the microscope all these rocks are seen to contain a rather unusual quantity of apatite in colourless acicular prisms. Magnetite occurs plentifully, in composite crystalline forms, in ragged grains and patches, and in crystal frameworks. These two minerals always have the priority in the order of consolidation. The augite is of the very pale-brown variety, and when it exhibits crystal outlines, has the familiar octagonal cross-section. Besides the well-defined prismatic cleavage, there are traces of another, transverse to the length of the prism. The mineral is usually fresh; its chief secondary product seems to be serpentine. ‘These characters, which are approached by the augite of many Welsh diabases, agree with the variety malacolite. Hornblende is plentiful in all but one slide [686]. It is the deep-brown ‘basaltic’ variety, with absorption-formula y > 6 >> a. The mineral occurs some- times in good prisms, truncated, except in the smallest crystals, by the clinopinacoid. Much of the hornblende, however, occurs in close association with the angite, the two minerals having, as usual, the vertical axis and orthodiagonal common. ‘The hornblende mostly borders the augite, and when there are definite crystal out- lines to such a border, they are those proper to the former mineral. This is, therefore, not a case of ‘paramorphism,’ but an inter- growth of the kind termed ergdnzende or complementary hornblende. Patches of hornblende in the interior of the augite plates are probably also a parallel intergrowth. The hornblende crystals occasionally enclose grains of augite without any crystallographic = Alfred Harker—On some Anglesey Dykes (No. III.) 271 relation, and in all cases the hornblende in these rocks seems to be in the main posterior to the pyroxene. Greenish fibrous amphibole is common as a ‘secondary enlargement ’ in crystalline continuity with the original hornblende, and it sometimes extends as a fringe along the margin of the augite. A similar relation is met with in some of the German hornblende-diabases, e.g. the ‘proterobase’ of Ktirenz near Trier. Striated felspar is always abundant in the rock of the dyke, and appears to belong mainly to the andesine-labradorite series. It is often strongly zoned, or if the felspars do not all belong to one stage, the later ones show this structure. In accordance with the usual rule, the outer zones always give lower extinction-angles than the inner part of the crystal. The only other mineral to be mentioned is biotite, of which a few flakes are seen in one slide (Bryniau Geirwen). The specimens present then, it is evident, a community of general mineralogical constitution, and the diversity of structure noted below is therefore a matter of some interest. . [626.] From the northern termination of the dyke. In this rock the augite has idiomorphic boundaries, and is moulded by the felspar. The general aspect to the eye is not unlike some gabbros. A specimen of Mr. Marr’s from Cae Seri is a rather coarse-grained gabbro-like rock. The felspar and augite penetrate one another in a rather curious way, and must on the whole have consolidated simultaneously. [635.] Bryniau Geirwen. This shows the same peculiar type of structure ; the augite sometimes presents crystal outlines to the felspar, which moulds it, while in other places these relations are reversed, the felspar crystals penetrating the augite. [636.] Bryniau Geirwen. This specimen, from the same locality as the last, is an ordinary ophitic diabase. Finally, a rock procured by Professor Hughes from the same place is also ophitic in structure, but shows a decided tendency to the doleritic type. There are two generations of felspar; one in lath- shaped crystals penetrates the augite and hornblende; the other, more equidimensional and without regular outlines, is of later con- solidation than those minerals. The existence of such wide differences of structure in rocks forming part of one and the same igneous mass, offers a problem of which petrologists have not yet given a complete solution. Henslow collected specimens from two dykes, the larger one having a width of eighteen feet, at Port Newry, near Holyhead town. As he remarked, the rock here much resembles “the harder portions of the dyke at Port Dafreth” [605]. The chief difference is the greater abundance of olivine. [688.] Olivine-dolerite of Port Newry. The olivine, which often builds good crystals and has the pinacoidal cleavages well developed, is on the whole the first product of consolidation, though sometimes slightly penetrated, as at Porth-dafarch, by the earliest-formed felspars. The mineral is for the most part pseudomorphed by green 202 Notices of Memoirs—H. Miller’s Study of the Till. serpentine in the fashion figured by Tschermak’ and others. The felspar of this rock seems by its extinction-angles to be near anorthite. ‘The most numerous generation is in elongated crystals with fine lamellation. There are also later felspars in shapeless crystals with wide twin-lamelle and strongly-marked zonary band- ing in polarised light. The magnetite is later than the dominant felspar and earlier than the augite; it sometimes shows rod-like aggregations of octahedra. The pale-brown augite, in plates with an ophitic tendency, has here again a marked hour-glass structure, although the dividing lines have often an irregular disposition, and even run parallel to the outlines of projecting felspar crystals. It may be remarked that the hour-glass augites of the Welsh rocks rarely exhibit the regularity of structure figured by Werveke, etc.’ Several rocks from Holyhead stand on the border-land between the diabases and dolerites, as those families are here defined. The present specimen seems best referred to the latter category, the porphyrische structur (Rosenbusch) being well marked: the absence of ilmenite and hornblende is also to be noted in this connection. Other dykes in Holyhead Island are marked on the Survey Map and mentioned by Sir A. Ramsay. They all strike in a general N.W.—S.E. direction, ‘“‘ which is also that of the fault which crosses Holyhead Mountain between Gogarth and Porth-y-corwgl, and all coincide more or less with the run of many of the larger joints.” We have seen that the dykes of the Menai Straits and the Coal-field have about the same bearing, but they show lithologically little resemblance with those last described ; and as the rocks cut by the Holyhead dykes are themselves of dubious age, speculation on the date of the dykes must necessarily be reserved. NOTICES OF MEMOTRS. Seas a TT IT.—A Comparative Stupy or THE TiLtL on Lower BouLDER-CLAY IN SEVERAL OF THE GLACIATED CountTRIES OF EHuropE—Britatn, SCANDINAVIA, GERMANY, SWITZERLAND, AND THE PyrENEES. By Hueu Miter, F.R.S.E., F.G.S., Assoc. R.S.M.° HE sections of foreign Till examined by the author occur chiefly in the neighbourhood of the Trondhjem Fjord in Norway, at Berlin and Leipzig in Germany, near the Lake of Geneva in Switzer- land, and in the valleys of the Pyrenees directly south from Pau. in Southern France. In these countries and in Britain the Till bears an identical character. It is not more variable throughout Europe than the author has found it to be in Scotland and Northern England. On the basement-gneiss at Christiansund in South-western Norway it is the same as on the basement-gneiss of Sutherlandshire; in the great limestone valley of Haux Chauds in the Pyrenees it is scarcely 1 Sitzungsb. d. k. Akad. d. Wien. vol. lvi. p. 283, and plate, 1867. 2 Neues Jahrbuch, 1879, p. 823. Hussak, Anleitwng zum bestimmen der gesteinbildenden Mineralien, p. 72; 1885. 3 Read at the British Association, Manchester, 1887. Reviews—The Geological Survey of England and Wales. 273 to be distinguished from the Till of the limestone valleys of York- shire. In all the places mentioned it bears the unmistakable character of a ground-moraine accreted under the direct weight of glacier-ice. The familiar features of the Till need not be recapitu- lated here, but the author insists that its essential character is that of a rude pavement of glaciated débris, ground from the rocks over which the glaciers have passed, with its larger boulders firmly glaciated in situ on their upper sides in the direction of ice-move- ment, and with a tendency to the production of fluxion structure here and there in the matrix, due to the onward drag of the superin- cumbent ice. In mere indiscriminateness of composition (which is the character often most emphasised) the Till is not to be distinguished from Boulder-clays formed under berg- or raft-ice, such as the highest marine clays of the Norwegian coasts, which are stuck promiscuously through with boulders derived from the glaciers of the interior. But the glaciation of boulders zn situ the author finds to be a really crucial distinction; he readily detected this “ sériated-pavement ” character in the Tills of all the districts above mentioned except Leipzig and Berlin, where the Boulder-clays resemble the Upper Boulder-clay (Hessle Clay) of the eastern seaboard of England and Scotland, and in the sections examined by him contained no blocks large enough to take the strie. 15%) Ja WW dB Jah WWASe —_—~—>_—_- J.—Tue GeroLtocicaL Survey or EnGLanp AND WALES. OME time has elapsed since we last noticed a series of the Geological Survey Memoirs (Grou. Mae. for 1886, p. 65), and in the mean time a number of additional Memoirs have been pub- lished, attention having been drawn to only one of these (Guot. Mac. 1888. p. 31). Much more detail is inserted in these Explana- tions of.the Survey Maps than was the custom in the earlier publications; but if on this account they afford somewhat heavier reading, they are also much more valuable for reference on questions both of scientific interest and of practical concern. Indeed the precise record of facts and a statement of the localities where particular information has been obtained, are always of great value to sub- sequent investigators, as well as to engineers and well-sinkers. We note also that the prices of these Memoirs are very moderate. In addition to a number of General Memoirs on particular districts or rocks, no less than 66 Memoirs explanatory of the Survey Maps have now been published. Nevertheless much remains to be done ere the whole country is described in such detail. Portions of Hampshire and Dorsetshire have not yet been ‘explained’ in Survey publications ; the Isle of Man and the Channel Islands have not at present been officially surveyed; while Cornwall and much of Devonshire, the South Wales Coal-field and the Old Red Sandstone area of Brecknock- Hereford- and Monmouth-shires offer tempting fields for future detailed surveys. Moreover, the Drift-deposits over DECADE III.—VOL. V.—NO. VI. 18 274 Reviews—The Geological Survey of England and Wales, considerable portions of the Midland Counties, not to mention other areas, have not at present been mapped. Our present object, however, is to notice the recent Memoirs, and these will be taken as far as possible in the order of publication. 1. “The Geology of the Country between and south of Bury St. Edmunds and Newmarket.” By F. J. Bennett and J. H. Blake; edited with additions by W. Whitaker, F.R.S. 8vo. pp. 27. (London, 1886.) Price 1s. This Memoir contains notices of the Chalk, Glacial Drift, River Gravels, etc. Interesting sections are given, showing the structure of the Glacial deposits and their relation to overlying ‘“ Post- Glacial” loam, which has yielded Paleolithic Implements. Numer- ous well-sections form an Appendix to the work. 2. “The Geology of the Country around Aldborough, Framling- ham, Orford, and Woodbridge.” By W. H. Dalton, edited (with some additions) by W. Whitaker, F.R.S. 8vo. pp. 59. (London, 1886.) Price 1s. The district described in this Memoir is one of great interest to students of Pliocene geology, including as it does some of the famous Crag-sections near Orford and Aldborough. Mr. Whitaker contributes notes on the fossils and on the literature of the Coralline Crag, but the details given on this formation are confined to two pages, and there is no list of fossils. The accounts of the Red Crag and of the Chillesford Clay are fuller so far as stratigraphical details are concerned, but we miss an account of the fossils. The Palaon- tology will doubtless be treated in a general Monograph of the Pliocene formation, which we are informed is in preparation. Short notices of the Chalk, Reading Beds and London Clay, and a more lengthy account of the Glacial Drift, are given, together with notes on the River Gravels, Alluvium, Shingle, and Blown Sand. The well-sections in the area are duly recorded. 3. “The Geology of the Country around Northallerton and Thirsk.” By C. Fox Strangways, A. G. Cameron, and G. Barrow. 8vo. pp. 75. (London, 1886.) Price 1s. 6d. The rocks described in this area include Millstone Grit, Magnesian Limestone (Permian), Keuper Sandstone and Marl, Rheetic Beds, Lias, Oolites (up to the Kimeridge Clay), Glacial and Recent deposits. The country embraces portions of the Cleveland, Hambleton, and Howardian Hills. The Memoir will be of particular interest to students of Jurassic Geology. Among the strata, the Ironstone series of the Middle Lias is of special economic importance, and detailed sections are inserted to show its mode of occurrence. Lists of fossils are given from the different formations. There is also an Appendix of well-sections, and a list of the more important works referring to the district. 4, “The Geology of the Country around Otterburn and Elsdon.” By Hugh Miller. With Notes by C. T. Clough. 8vo. pp. 147. (London, 1887.) Price 2s. 6d. This is the first Memoir of the Geological Survey devoted to the Carboniferous Rocks of the English Border, and a full description Reviews—The Geological Survey of England and Wales, 275 has been given of them. Some older rocks are exposed in the area, the Wenlock Beds and Lower Old Red Sandstone (associated with the Cheviot porphyrite), but they occupy small areas, and require but brief notice. The Carboniferous rocks are grouped as follows :— Upper Series. Calcareous Division. CO ae Carbonaceous Division (Scremerston Beds). Series Fell Sandstones. Lower Series. ) Tuedian Division, or | Cement-stone Beds & Roth- | Tweed Beds. bury Limestones. Lower Freestones. Basement Beds. The Basement Beds are probably on the horizon of strata else- where grouped as Upper Old Red Sandstone. They consist of conglomerates made up of porphyrite and Silurian greywacke. The overlying rocks are described in much detail, many sections being given to show the position of the principal beds of limestone, coal, etc. Separate chapters are devoted to the Faults, and to the Palzontology, the fossils having been identified chiefly by Messrs. G. Sharman and EH. T. Newton. Other chapters are devoted to the Jeneous rocks, to Glacial Phenomena, Post-Glacial deposits, and to the Physical History of the district. The Economic deposits, Springs, Mineral Waters, etc., are duly noticed, and in Appendices there is an account of the Bibliography, together with a Glossary of Local Terms, and Records of Borings and Sinkings. 5. “The Geology of the Country around Halesworth and Harle- ston.” By W. Whitaker, F.R.S., and W. H. Dalton. 8vo. pp. vi. and 41. (London, 1887.) Price Is. In this Memoir accounts are given of the Upper Crag (which is rarely fossiliferous in the area), of Chillesford Clay, Pebbly Series, Glacial and Post-Glacial Drift, and Alluvium. The deposits which have attracted most attention are those included as Post-Glacial, the term being used to imply that the beds are newer than the Glacial Drifts of the district. These are the famous Hoxne deposits, which have yielded many Paleolithic implements. Their precise age with reference to the newer Glacial deposits of the north of England may be regarded as an open question: but Mr. Dalton remarks that “The mere presence of land and freshwater shells, bones, and plants would suffice to disprove this correlation with any part of the Glacial series, which is wholly of marine origin.” We presume he refers to the Glacial Drifts of Norfolk and Suffolk, but that they are wholly of marine origin is very far from being an accepted dogma. A number of records of well-sections conclude this work; these give accounts of the London Clay, Reading Beds, and Chalk, which are not exposed at the surface. 6. “The Geology of Southwold and of the Suffolk Coast from Dunwich to Covehithe.” By W. Whitaker, F.R.S. S8vo. pp. 87. (London, 1887.) Price 2s. 6d. Although the area described in this Memoir is a small one (being less than 50 square miles), it is one of considerable interest to students of Pliocene Geology. The cliffs of Dunwich, Haston 276 Reviews—The Geological Survey of England and Wales. Bavent, and Covehithe furnish sections of the Upper Crag (including the Chillesford Beds) ; these strata are overlaid by a ‘‘ Pebbly Series,” and the question of their precise equivalents in other parts of the country is a debatable one; while above all there are accumula- tions of Glacial Drift. A well-boring at Southwold, made in 1886- 1887, has thrown much light on the underground geology, for it has proved the position of the Chalk at a depth of 3238 feet; this is overlain by 70 feet of Reading Beds, 68 feet of London Clay, 147 feet of Crag, and 87 feet of the Pebbly Series. The thickness of the Crag, as remarked by Mr. Whitaker, is the greatest yet recorded in England, and shows, together with the information obtained through wells at Leiston, Saxmundham, and Beccles, that the formation has a more important development than was suspected a few years ago. Whether this great thickness of Crag should be classed with the Norwich or Red Crag matters little, for, as Mr. Whitaker remarks, they are one formation, and “no useful purpose would be served by troubling about such a question.” There is, however, no evidence to show that the highest stage of the Norwich Crag series (such as that represented in the fossiliferous beds of Weybourn and the Bure. Valley) is here present, unless it be repre- sented in portions of the ‘‘ Pebbly Series” that are fossiliferous near Southwold. The “ Pebbly Series,” however, presents many difficulties. Much of what is now grouped under this name was originally regarded as Middle Glacial by Messrs. S. V. Wood and Harmer in their Map and Sections of the Crag District, and although Mr. Wood subsequently modified his views, there does not appear to be any definite evidence for the change, and an examination of the Survey Map is not calcu- lated to dispel the notion. These difficulties in correlation are apparent to any one studying the Newer Pliocene and Glacial Deposits of Hast Anglia, and they are very fully and fairly stated by Mr. Whitaker. He is disposed to regard the Pebbly Series as belonging to one division, and he leaves it an open question whether it should be regarded as Glacial or Pliocene. he shells found in the beds at Southwold are all species known to occur in the Crag; but neither there nor at Dunwich is the Crag separated from the Pebbly Series by the Chillesford Beds which are present in many localities. On the other hand, where the mass of the Pebbly Series rests on the Chillesford Beds, as seen in the Cliff-sections of Easton Bavent and Covehithe, there is a marked line of erosion between them ; while in a section at Henham Park Wood (drawn by the late Mr. 8. V. Wood, jun.), the Pebbly Beds are shown to rest on the Chilles- ford Clay, and tongues of the latter which penetrate the overlying beds are said to have been “lifted up.” In reference to this Mr. Whitaker remarks that “The lifting up of masses of this clay and the forcing under them of wedges of the pebbly beds is an oceur- rence of great interest,” and ‘seems to point also to some lapse of time between the two deposits.” We feel, however, some hesitation in adopting the explanation, which is suggestive of Glacial action, for there is no Boulder-clay present. Reviews—The Life and Works of Prof. Oswald Heer, 277 We should mention that a detailed account is given of the Cliff sections, and this is admirably illustrated by a coloured diagram drawn to scale. The accounts of the coast-deposits and of the waste of the cliffs are also of much interest, careful calculations showing that at Covehithe the annual loss of land is between 18 and 19 feet! Records of well-sections, and a list of the fossils, are also given in this Memoir. 7. “The Geology of the Carboniferous Limestone, Yoredale Rocks, and Millstone Grit of North Derbyshire.” By Prof. A. H. Green, F.R.S., Dr. C. Le Neve Foster, and J. R. Dakyns. Second edition, with additions by Prof. Green and A. Strahan. S8vo. pp. xv. and 212. (London, 1887.) Price 5s. 6d. A new edition of this Memoir (which was published originally in 1869) has long been wanted, for the district is one that offers many attractions to the geologist. Some changes are made in the classifica- tion of the Millstone Grit and Yoredale Rocks. The portion relating to the Drift has been enlarged, and a small map has been given (p. 97) to show the glaciation of the north-west of England. There is also much additional information about the Caves, Springs, etc., and on the subject of Mining. The list of fossils from the Carboniferous Limestone has been revised, and a Bibliographical List has been appended. 8. “The Geology of the Country around Kendal, Sedbergh, Bowness, and Tebay.” By W. Talbot Aveline, and Prof. T. M‘K. Hughes. Second edition by A. Strahan. Parts by J. R. Dakyns and R. H. Tiddeman. 8vo. pp. 94. (London, 1888.) Price 2s. The former edition of this Memoir was published in 1871, since then the area has been re-surveyed for Drift. A great deal of new information has been obtained respecting the Volcanic series of Borrowdale, the Coniston Limestone Series, the Stockdale Shales, the Carboniferous rocks, the Shap granite, and the Glacial phenomena. Full lists of fossils are given, and there is also a Table showing the distribution of the Graptolites, by Prof. Lapworth. IJ.—Two Works oN THE LATE Proressor HEER. 1. Oswatp Herr: LrEBENSBILD EINES SCHWEIZERISCHEN NATUR- FORSCHERS: I. Dir JuGenpzerr, von Justus Herr; 144 pages, with a Photographic Portrait. JI. & III. O. Heer’s Forscusr- ARBEIT UND DESSEN PERSONLICHKEIT, von C. ScHROTER, unter Mitwirkung von Gustav Strertin und GorrrrrepD Herr; 543 pages, 8vo. with a Coloured Plate and many Woodcuts taken from ‘‘The Primeval World of Switzerland.” (Zurich, P. Schulthess, 1887). likes great influence exerted by the late Prof. Heer on different branches of Natural History, and especially on the develop- ment of paleobotany, has very naturally given rise to the work mentioned above. It contains a sketch of Heer’s life and an analysis of his many different works. The author of the first part is Heer’s brother, the late Rev. Justus Heer, who gives a very 278 Reviews—The Life and Works of Prof. Oswald Heer. interesting sketch of the early years of the great paleobotanist. His love for nature began in his early youth, which was passed in the little Alpine village of Matt, of which his father was the clergy- man. He first studied the flora and fauna (more especially the insects) of the districts near his home, and subsequently extended his researches to the higher regions of the Alps. He became an intrepid and skilful climber, and the numerous botanical and ento- mological discoveries made by him in these little accessible regions attracted the notice of many well-known scientific men of his native land. In deference to his father’s wish, he had, however, to give up his inclination for scientific pursuits, and betake himself to the University of Halle to prepare for a clerical career. After returning to Switzerland, he declined the offer of a life-long appointment as clergyman, and preferred rather to accept a temporary engagement to arrange and determine the large entomological collections of Hscher-Zollikofer ; thus definitely undertaking a scientific career. The second and third parts of the volume are devoted to a critical review of Heer’s scientific work, and a sketch of his personal character ; the former is more especially interesting since the matters treated are still of the first importance. Dr. Schréter refers first to Heer’s work on recent plants, more particularly regarding their geographical distribution, both generally and in the different regions of the Alps. Late in life, Heer again turned his attention to the origin of the Alpine flora, as shown in his posthumous treatise “Die nivale Flora der Schweiz.” Equally valuable are his researches on the ancient history of still existing plants, and his paper on the plants of the ancient lake-dwellings (Die Pflanzen der Pfahlbauten) is a genuine classical treatise. Heer’s many other botanical works cannot even be mentioned here. Then comes a chapter, written by Dr. Stierlin, giving a review of Heeyr’s contributions to the knowledge of recent and fossil insects. It is an interesting fact that Heer treated the beetles of Switzerland from precisely the same points of view as the plants; regarding not only their systematic position, but their geographical distribution as well. He was therefore very familiar with the laws of the geogra- phical distribution of plants and animals when he commenced his studies on the ancient floras and insect faunas of the globe. His remarks on the habits and intellectual powers of a species of ant from Madeira (Ccophthora pusilla) give great credit to his keen faculty of observation. Heer’s contributions to fossil entomology are indeed astonishing. They will be best understood from the fact that at the time he began his work only about 200 species of fossil insects were known; and he was able from Switzerland alone to describe more than 1000 fossil species, of which 143 were from the Liassic strata of Scham- belen, and 876 species from Tertiary beds of other parts of the same country. Besides these, he described a great number of species from the Tertiary deposits of Radoboj and Aix; from the Rheetic beds of Scania, as well as from the Arctic regions, etc. Any one who has read the ‘“ Primeval World of Switzerland” will call to mind the Reviews—The Life and Works of Prof. Oswald Heer. 279 number of ingenious conclusions which Heer has drawn from the presence of these creatures in the rocks—conclusions which could only have been arrived at by one who was thoroughly familiar with the habits of existing forms. Dr. Schréter devotes several chapters to the most important part of Heer’s life-work—namely, his contributions to fossil botany. After passing in review the work done in this branch of science before Heer contributed to it, he proceeds at once to the considera- tion of the important question as to the reliability of the determina- tions from dicotyledonous leaves. It has been generally supposed that Heer was himself satisfied as to the validity of determinations thus based; but, as Prof. Schréter points out, this is by no means the case. Heer has thus expressed his views on the point: “ In those instances, where the form of the leaves and their nervation are very characteristic, we may, at least with great probability, determine the plant from them ; in other cases, its systematic position must be regarded as doubtful until other portions of the plant have been discovered, by means of which the characters drawn from the leaves are corroborated. Leaves of this latter category are of little value from a systematic point of view, but they may, notwithstanding, be of great service in the determination of the geological horizon in which they occur. The systematic position of Myrica dryandrefolia, Brongniart, was thus for a long time doubtful. Brongniart himself referred the leaves to Comptonia, Ettingshausen to Dryandra, whilst Saporta was able at last to show that Brongniart’s opinion was correct. But although it was for a long time doubtful whether the leaves belonged to Myricacee or to the Proteacee, they nevertheless did good service as characteristic fossils.” Dr. Schréter is quite right in stating that it is unfortunate for the credit of phytopaleontology that names must be given even to those leaves of which the systematic position cannot be ascertained. The mischief would, however, to a certain extent, be avoided by the adoption of the method proposed by the reviewer, that no fossil leaf from strata older than the Pliocene should be placed under an exist- ing genus unless its generic relationship is sufficiently proved by other evidence, in addition to that of the leaf itself. When this cannot be shown, the leaf should either be given an independent generic name, such as Credneria, Dewalquea, Protophyllum, etc., or a name compounded of an existing genus with the suffix phyllum. A name of this character would not exclude the idea that the leaf in question might belong to the existing genus, it would only indicate that its congeneric identity had not been proved. If all fossil dicotyledonous genera were revised on this system, we should find that most of the Cretaceous forms would be brought under Magnolv- phyllum, Populiphyllum, Lauriphyllum, Platanophyllum, etc., instead of Magnolia, Populus, Laurus, and Platanus. Of Tertiary plants, a greater percentage would be brought within existing genera, but others would have to retain the provisional suffix phyllum. It might even happen that both generic names could be used for different species from the same deposits, as, for example, Acer arcticum and 280 Reviews—The Life and Works of Prof. Oswald Heer. Aceriphyllum inequale. Then we should know at once that the former species had been proved to belong to the genus Acer, whilst the generic position of the latter was still uncertain. In this way the palzeobotanist would be able to express the precise aces ee of our knowledge of a fossil plant. Dr. Schréter is not an uncritical admirer of everything alain Heer has done, but whilst expressing the opinion that Heer had gone too far in determining genera from dicotyledonous leaves, he gently remarks that it has nevertheless been fortunate for science that he had the courage to proceed as far as he did, for otherwise a great number of fossil leaves, which have been rightly determined, and which have proved of the greatest value in furthering our knowledge of the geographical distribution of plants, and of the climates ‘of former epochs, would have been either overlooked or not described. And even supposing that in some cases Heer’s determinations of fossil leaves have been insufficiently based, these are more than counterbalanced by the importance of those correctly worked out. According to Dr. Schréter, the total number of new species described by Heer amounts to 1947, and, in addition to these, he has described numerous forms to which names had been already applied by others. These descriptions of fossil plants were accompanied by as many as 704 plates. Heer had indeed the satisfaction to find that the merits of his works were acknowledged by most competent judges, amongst others by Sir Joseph Hooker, who pronounced, as his ‘candid opinion,” that at least two-thirds of Heer’s determinations of fossil genera and families were quite correct, and that those correctly determined included nearly everything of importance. Even Lyell was fully convinced of the correctness of Heer’s determinations of Tertiary plants. Under these circumstances it is probable that the attacks made, from time to time, on Heer’s methods and results, owe their origin either to imperfect knowledge, or to a misunderstanding of what he has done. Of course, since the time when Heer wrote there have been great advances made in paleeobotany, as in every other science, and it is not surprising, therefore, that the methods he followed should now be partly supplanted by better ones. But if we are to condemn every honest worker of a previous age simply because his methods do not agree with our own, who would then escape con- demnation? There is no doubt that Heer, in common with every other scientific writer, has made mistakes; but these are so much more than counterbalanced by the excellent work he has done, that it would be decidedly unfair to dwell only on the former, without taking the latter into account. Much has been written lately on the question whether certain deposits, pronounced by Heer to be of Miocene age, might not, in reality, belong to the Eocene. The question is still undecided; but even if some of these deposits should ultimately prove to be of Eocene age, it must not be forgotten that but little was known of 1 For further details compare the paper by the reviewer in the “ Botanisches Centralblatt,’’ 1886, vol. 25, Ueber die Benennung fossiler Dikotylenblatter. Reviews—The Life and Works of Prof. Oswald Heer. 281 Eocene floras when Heer wrote, and that the present abundant materials for comparison did not then exist. Want of space prevents our giving an exhaustive analysis of Dr. Schriter’s work. Besides a review of Heer’s “ Primaeval World of Switzerland,” so well known to the scientific world of England, and an exhaustive criticism of the ‘Flora fossilis arctica” (seven vols. 4to. 398 plates, 1868-83), it treats of Heer’s contributions to several scientific problems. We may here call to mind that Heer was the first paleeobotanist who expressed the opinion that the polar regions had been the centre of distribution for a multitude of plants, especially since Cretaceous and Tertiary times, and this view was developed and defended in many of his works. It is therefore very annoying, Dr. Schréter says, to find a statement in ‘“ Nature,” ?* in which Heer is specifically excluded from the list of naturalists who are said to have rendered services to the theory of the migration of plants from the polar regions. Dr. Schréter gives, further, an exposition of Heer’s contributions to the Climatology of ancient epochs; of his phylogenetical studies of different genera and families, and of his position towards the theory of evolution. Heer has generally been regarded as an antagonist to this theory, but this is so far from correct, that he should rather be considered as one of the precursors of Darwin. Already, in 1855, Heer pronounced the opinion that species owed their origin to other species, and he may therefore be looked upon as an evolutionist (compare also Life of Lyell, part ii. p. 246), even though he did not believe in the gradual development of species, but considered that the transitional changes were sudden, and occurred during certain short periods. The great productivity of Heer as a scientific author, and the diversity of subjects he treated, make it very difficult to obtain a full comprehensive view of his scientific achievements. Next to con- sulting his original works, the present volume affords us the best idea of the entire life-work of the great paleeobotanist of Zurich. No doubt Dr. Schréter’s task has been a very difficult one, and there is therefore the more reason to congratulate him on having accom- plished it in such a successful manner. A. G. Natuorst. 2. Oswatp Herr: BIBLiIoGRAPHIE ET TABLES ICONOGRAPHIQUES, PAR GoprEFRoY MatLnoizeEL; PRECEDE D'UNE NOTICE BIOGRA- PHIQUE PAR R. ZEILLER; AVEC UN PORTRAIT D’OswaLp HEER. Svo. pp 176.. (Stockholm, F. & G. Beijer, 1888.) HE volume now under consideration may be said to complete and supplement that by Dr. Schroiter, noticed above. Whilst this latter gives a sketch of Heer’s life, and a general analysis of his scientific works, the present volume is intended to facilitate references to the works themselves. The biographical sketch by M. Zeiller is limited to ten pages; the rest of the volume by M. Malloizel, Sub- Librarian of the Museum of Natural History, Paris, contains a com- 1 May, 1879, p. 12. 282 Reports and Proceedings— plete list of the various works, articles and notes published by Heer, arranged according to their dates of publication, which extend from 1832 to 1884. This list comprises from 270 to 280 titles, and it is followed by lists of the fossil animals (except the insects) in “ Die Urwelt der Schweiz” ; of the insects figured in Heer’s various works, and of all the fossil plants described and figured by Heer. As the references include the page, plate, and number of figure for each species, it is evident that the work will prove of immense service to paleobotanists and others desirous of consulting Heer’s works. I can state from my own experience that it has already been of much service to me, and a great saving of time and trouble, and M. Malloizel deserves the thanks of all paleobotanists for undertaking the tedious task of preparing this compilation. A. G. Naruorst. cE @ eS) Aa i> O@ Cia aING Ss ee GrotoeicaL Society or Lonpon. I.—April 25, 1888.—W. T. Blanford, LL.D., F.R.S., President, in the Chair.—The following communications were read :— 1. “Report on the Recent Work of the Geological Survey in the North-west Highlands of Scotland, based on the field-notes and maps of Messrs. Peach, Horne, Gunn, Clough, Hinxman, and Cadell.” Communicated by A. Geikie, LL.D., F.R.S., F.G.S., Director-General. At the outset a review was given of the researches of other observers, in so far as they forestalled the conclusions to which the Geological Survey had been led. Reference was made to the obser- vations of Macculloch, Hay Cunningham, C. W. Peach, and Salter ; to the prolonged controversy between Sir Roderick Murchison and Professor Nicol ; to the contributions of Hicks, Bonney, Hudleston, Callaway, Lapworth, Teall, and others. It was shown that Nicol was undoubtedly right in maintaining that there was no conformable sequence from the fossiliferous quartzites and limestones into the eastern schists. It was also pointed out that the conclusions of Professor Lapworth regarding the nature and origin of the eastern schists involve an important departure from Nicol’s position, and are practically identical with those obtained independently by the Geological Survey. The results of the recent survey work among the Archean rocks may be thus summarized :—(1) the eruption of a series of igneous rocks of a basic type in which pegmatites were formed; (2) the development of rude foliation in these masses, probably by mechanical movement, and their arrangement in gentle anticlines and synclines, the axes of which generally run N.H. and 8.W.; (8) the injection of igneous materials, mainly in the form of dykes, into the original gneisses, composed of (a) basalt rocks, (b) peridotites and paleo- picrites, (¢) microcline-mica rocks, (d) granites; (4) the occurrence of mechanical movements giving rise to disruption-lines trending N.W. and S.E., E. and W., N.E. and S.W.; (5) the effects of these movements on the dykes were to change the basalt-rocks into diorites Geological Society of London. 283 and hornblende-schists, the peridotites and palzeopicrites into talcose schists, the microcline-mica rocks into mica-schists, and the granites into granitoid gneiss; (6) the effects on the gneiss resulted in the formation of sharp folds trending generally N.W. and 8.E., the partial or complete reconstruction of the original gneiss along the old foliation-planes, and finally the development of newer schistosity more or less parallel with the prominent disruption-lines. There is an overwhelming amount of evidence to prove that all these various changes had been superinduced in the Archzan rocks in Pre-Cambrian time. After reviewing the facts bearing on the denudation of the Archean land-surface, the order of succession and thickness of the Cambrian strata were given, from which it is apparent that the deposits gradually increase in thickness as we pass southwards from Durness to Loch Broom. Prior to the deposition of the Silurian sediments the Cambrian strata were folded and extensively denuded. By these means various Cambrian outliers were formed far to the east of the present limits of the formation. The order of succession of the Silurian strata along the line of complicated structure from Eriboll to Ullapool was described, refer- ence being made to the further subdivision of the ‘“ Pipe-rock” and the Ghrudaidh Limestones (Group I. of Durness section). None of the richly fossiliferous zones of Durness is met with along this line, as they occupy higher horizons. An examination of the fossils recently obtained by the Geological Survey from the Durness Lime- stones confirms Salter’s conclusions that they are distinctly of an American type, the Sutherland quartzites and limestones being represented by the Potsdam Sandstones and Calciferous Sand Group of North America. After the deposition of the limestones, the Cambrian and Silurian strata were pierced by igneous rocks, mainly in the form of sheets, producing important alterations in the sedimentary deposits by con- tact-metamorphism, the quartzites becoming crystalline, and the limestones being converted into marble. When this outburst of volcanic activity had ceased, terrestrial dis- placements ensued on a stupendous scale. By means of powerful thrusts the Silurian strata were piled on each other, and huge slices of the old Archean platform, with the Cambrian and Silurian strata resting on it, were driven westwards for miles. With the view of illustrating the extraordinary complications produced by these movements, a series of horizontal sections was described drawn across the line between Hriboll and Ullapool. The evidence relating to regional metamorphism was next referred to, from which it is obvious that with each successive maximum thrust there is a progressive amount of alteration in the displaced masses, as the observer passes eastwards to the higher thrust-planes. Eventually the Archean gneiss is so deformed that the Pre-Cam- brian foliation disappears and is replaced by new divisional planes ; the Cambrian grits and shales are converted into schists ; the Silurian 284 Reports and Proceedings—Geological Society of London. quartzites into quartz-schists; the limestones become crystalline ; the sheets of intrusive felsite, diorite, and granitoid rock pass into sericite schist, hornblende-schist, and augen-gneiss respectively. The researches furnish a vast amount of evidence in support of the theory that regional metamorphism is due to the dynamical and chemical effects of mechanical movement acting on crystalline and clastic rocks. It is also clear that regional metamorphism need not be confined to any particular geological period, because in the N.W. Highlands, both in Pre-Cambrian time and after the deposition of the Durness Limestone (Lower Silurian), crystalline schists and gneiss were produced on a magnificent scale. 2. «On the Horizontal Movements of Rocks, and the Relation of these Movements to the Formation of Dykes and Faults and to Denudation and the Thickening of Strata. ” By William Barlow, Hsq., F.G.S. The paper commenced with a description of some horizontal move- ments of rocks caused by gravitation; and the author quoted Mr. C. EK. Dutton’s descriptions of the Grand Cafion District, especially noting the fact that between succeeding escarpments the strata dip slightly from the crest of the one below to the foot of the next above, and that whilst the strata of the median parts of each terrace are nearly horizontal, the inclination increases as we approach the escarpment of the next higher terrace, and also that Dutton observed indications of a slight elevation of the unloaded strata within the denuded elliptical area known as the “San Rafael Swell.” After alluding to Dutton’s suggestion that the phenomenon referred to is analogous to the action “of creeping in deep mines, the author dis- Cagced the nature of such “ creeps,” which he deared as the thicken- ing of the parts of beds from which a load of superincumbent rock has been lifted, caused by a thinning of the adjoining parts which remained loaded, some of the substance of the latter having been squeezed out to furnish the material for the thickening, and suggested that some of the subsidiary plications found on the flanks of moun- tains are caused by the thrusts arising from creeps. He also paralleled the fissures in the precipices of the Grand Cation District with those produced in the pillars of coal owing to the strain induced by the slight inequality in the yielding of the bed supporting it, and pointed out how such fissures would facilitate denudation, giving instances recorded by Dutton, and that an appreciable influence might be thus produced in all cases of mountain-denudation. The author next considered the case of a body of molten rock below a considerable mass of solid rock. The pressure upon the molten mass would cause movement to take place towards the point where the superincumbent weight was least, provided that absolute equilibrium did not exist. The overlying rocks being more or less plastic, some horizontal movement of the solid rocks at the confines of the molten mass, and subjected to its influence, might be looked for. Any such yielding would tend to draw apart the solid crust resting upon the molten rock, and the ground would open along lines of weakness, such as would be produced by the presence of joints, the crust in some cases breaking up into larger or smaller fragments. Correspondence—Prof. T. G. Bonney. 285 When a large mass of molten matter occurred near the surface, and a fissure was produced in the way described, the weight of the ruptured crust would, if the plastic mass beneath were sufficiently liquid, cause the latter to rise in the fissure, producing dykes. Attention was called to the fact observed by Dutton that basaltic vents frequently occur on the brink of cliffs, but never at their bases; also to the existence of dykes having a strike parallel to the Colorado River. In most cases the vertical fissures which received the molten rock would begin to open from below, and the upper strata might altogether escape rupture. The author discussed the case of the Henry Mountains, and explained the formation of flat-topped and flat-bottomed dykes according to his views. He next called attention to the influence which the motions of the rocks had exercised in determining direc- tions of drainage when fissures left unfilled became occupied by streams. He next alluded to river-valleys, the existence of which had been accounted for by “ antecedent’? and ‘“ superimposed” drainage, and suggested difficulties in the way of accepting the explanations hitherto advanced, and considered them to be instances of fissuring produced by movements of the strata due to the pressure of a mass of molten or highly plastic rock spreading laterally. After treating of the formation of faults with normal hade, which he referred in some cases to rupture of the solid crust by the spread of a vast mass of viscous matter lying beneath it (the faults being sometimes replaced above by monoclinal folds), he referred in con- clusion to the extent of the horizontal compression of the earth’s superficial crust, which is seen to be associated with the elevation of mountain-ranges, and called attention to some evidence that the thickening of the strata caused thereby would be more considerable and general than ordinarily supposed. 3. “ Notes on a Recent Discovery of Stigmaria ficoides at Clayton, Yorkshire.” By Samuel A. Adamson, Esq., F.G.S. The specimen described was obtained in November, 1887, from the beds between the Better-bed Coal and the Elland Flagstone of the Fall-top Quarries of Messrs. Murgatroyd. The author gave measure- ments of the specimen, and compared them with those of another found in the same quarry in 1886, and now preserved in the Owens College, and with those of a third obtained in an adjoining quarry. COE ea S24 Oi > NS sae —_—<—_@__—_—_—_ ROUNDING OF PEBBLES BY ALPINE RIVERS. Sir,—Mr. Irving’s remarks in your last number appear to call for a few words in reply. As my paper was entitled “On the Rounding of Pebbles by Alpine Rivers,” I fail to see that I was bound to discuss other modes of forming pebbles, unless they seriously interfered with the inductions which I was attempting to draw. Hence, I did not mention “the weathering of débris on the mountain sides,” because, so far as that had a bearing on my subject, 286 Correspondence—Prof. T. G. Bonney. it strengthened my argument, which was to show that a respectable pebble was not easily made by running water, and because, in the case of the rocks with which I was dealing, the rounding mentioned by Mr. Irving is, as a rule, a very secondary and subordinate matter. (1.) Every one knows that certain rocks become tolerably rounded by mere aérial waste, but the débris which reaches Alpine torrents (in the districts of which I spoke) is commonly angular; and this is equally true of the material to which my inferences applied. I may add that I believe few things are more important in attempting to reason inductively from observed facts than to be careful in pre- serving a due relation between quantities of the first and second order of magnitude (as they are called by mathematicians). Over- much precision of statement and an elaborate parade of small details interfere with our sense of proportion, and there is great danger, if you look at a sprat for too long a time, and from too near a point of view, that you may at last fancy it a whale. (2.) In regard to “the scouring action of sand,” I cannot pretend to say how much is done by the knocking of the pebbles together, and how much by the friction of passing sand ; but I certainly cannot make the distinction which Mr. Irving attempts todo. All the rivers of which I spoke transport quantities of sand as well as pebbles in all parts of their course, though it is only in the lower part that they can deposit much of the former. However, as it takes a very long journey to remove the angles from a grain of sand, I have my doubts as to its conspicuous efficiency as a fashioner of pebbles out of pieces of hard rock, and if Mr. Irving alludes to the action of sand on pebbles which but rarely travel, then I think it would tend to flatten rather than to round them. (3.) In regard to the general question raised, viz. the origin of the pebbles and other materials of the Bunter group, space will not permit me to enter into details, so I must forbear to criticize minor but not unimportant points in Mr. Irving’s letter, such as ‘the pebble-beds proper being quite local,” a statement which is only true if a most liberally extended sense be given to the last word. But I express a fundamental dissent by asking whether there is any evidence at all in favour of the Bunter being a marine deposit, and still more a deposit in a sea where, according to the ordinary rules, strong coast currents or a rolling surf would be likely to exist. All I can say is that the Bunter as a whole is remarkably unlike every admitted marine formation which I have ever examined, while it presents a strong resemblance to such deposits as parts of the Old Red Sandstone, some beds in the Lower Carboniferous of Scotland, and the Nagelflue of the Alps: deposits, which most geologists agree in considering more or less fluviatile: nay, allowing for a slight difference in colour and hardness, the Bunter pebble-beds of Central England (I said nothing about Southern England) are indistinguish- able from many of the old sub-Alpine river-drifts which I have repeatedly examined. T. G. Bonney. Correspondence—Rev. G. Crewdson—IUr. A. Somervail. 287 GRAPHITE AT KENDAL. Str.—A few days ago, in digging a grave in the cemetery at Kendal, a piece of graphite weighing about five ounces was found in the Glacial Drift of which the ground is composed. The cemetery is at the southern base of the Castle Hill, a large drumlin containing boulders and gravel, of Shap granite, Kirkby Moor flags (Ludlow), Ash (Borrowdale series), and other rocks. The granite is only found on the northern half of the hill. The other rocks might be derived from the valleys which converge on Kendal or in the line of boulder flow from Shap. Unfortunately the graphite was not found in undisturbed drift. It lay a short distance above the lid of the coffin of an earlier inter- ment made about 17 years ago. But it was so coated with soil that if it had not been accidentally scratched with the spade in digging, the sexton would not have noticed anything peculiar about it, and it is very probable that it may have been thrown out when the original grave was made, and reburied when the grave was filled in. That it was brought by other than nature’s agency is not likely. It was not usual at the date of the earlier interment to place ornaments on the graves, and the piece of graphite is not an article likely to be used for that purpose. Probably therefore it has been brought down with the drift from some deposit of graphite to the North or North-Hast. It is not likely to have come from Borrowdale; for I know of no instance of the discovery of any rock which can be distinctly traced to that region in the Kendal drift. Graphite being rare and destructible, I thought it might be of interest to record the discovery. Gro. CREWDSON. St. Grorce’s VicARAGE, KENDAL, 9th May, 1888. THE METAMORPHIC ROCKS OF SOUTH DEVON. Str,—In reply to Miss C. A. Raisin’s letter (see Grou. Maa. p- 190) the chloritic rock is a little on the north (or more correctly the north-west) side of Prof. Bonney’s fault-line where first indicated at the commencement of his ‘true schists.” These schists are also in their line of strike, on the south side of the chloritic rock. A recent visit has, however, enabled me to find these chloritic rocks still further north, across the stream on the north flank of the valley, so that the stream cannot be regarded as marking a line of fault, which from physical appearances it might seem to do. 59, Furer Srreet, Toravay. AuEx. SOMERVAIL. OS ORAS Ya = it WALTER KEEPING, M.A., BORN JANUARY 6, 1854; DIED FEBRUARY 22, 1888. Mr. Watrer Keerprne has for six years been lost to his friends and to science. In the vigour of early manhood he was somewhat 288 Obituary— Waiter Keeping, M.A. suddenly struck down by a form of paralysis, well known to medical men, which seldom spares its victim so long as in the present case. Previous to those six years we see him in full intellectual activity, after.a distinguished University career and a period of further train- ing as a teacher himself, settled down in charge of the magnificent collections in the York Museum, and giving promise of much valuable work for science. His early education was carried on alongside of work, which he had to perform in positions of more or less importance and trust, ending in the post of assistant to his father in the Woodwardian Museum. At the age of 19 he won a Scholarship at Christ’s College, and in due course graduated, obtaining a distinguished position in the First Class of the Natural Sciences Tripos of 1877. He con- tinued to work in the Woodwardian Museum until he was appointed Professor of Natural Science in the University College of Wales at Aberystwith. His quickness of observation always attracted him to the study of the Geology of the district in which he resided. The Lower Greensand of the neighbourhood of Cambridge, with its derivative fossils and rocks, as well as those which belonged to the age of the deposit, had received great importance from the economic value of the phosphatic nodules it contained, and early engaged his attention. It was then beginning to be the fashion to speak of it as Neocomian. In 1875 he published a paper in the GrotocicaAL Macazine on “The Occurrence of Neocomian . Sands with Phosphatic Nodules at Brickhill.” Five years later he con- tributed a paper to this Macazrnz on “The Included Pebbles of the Upper Neocomian Sands of the South Hast of England, especially those of the Upware and Potton Pebble-beds”; and in 1883 the Sedgwick Prize was awarded him for his Essay upon ‘'The Fossils and Paleontological Affinities of the Neocomian Deposits of Upware and Brickhill.” He was especially interested in the Echinodermata, and in 1876 and 1878 contributed some valuable Paleontological Notes to the Journal of the Geological Society in his papers on Paleozoic Echini ; on the Discovery of Melonites in Britain; and on Pelanechinus, anew genus of sea-urchins from the Coral Rag. On his appointment to the Chair of Natural Science at Aberyst- with, he turned his attention to the geology of the surrounding district, which he described in this Magazine in 1878, and ina paper on “ The Geology of Central Wales,” read before the Geological Society in 1881. These and various other notes and papers, recording observations made by him in the British Isles and on the Continent, show a keen perception of details and a power of generalization, which led his friends to anticipate for him a long career of distinction and useful: work. But soon after his appointment to the Curatorship of the York Museum, his health broke down, and after six years painful illness, he passed away in February, 1888. Tos. McKrnny Hucues. Decade HI Vol. V.PL IX, Tetsi@}., dl. Geol. Mag 1888. West, Newman &Co.imp. GM Woodward del.et lth. rb. Calamites undulatus, Ste THE GEOLOGICAL MAGAZINE. NEW. SERIES. DECADE” Il “VOLE VA No. VII.—JULY, 1888. @2E kG SIN AS Ee eAGr: ik Giese Si er I.—Woopwarpian Muszeum Notes. On CazAmMirEs UNDULATUS (Sternb.). By AuBert C. Sewarp, B.A., F.G.S., Foundation Scholar of St. John’s College, Cambridge. (PLATE IX.) T the end of his monograph on the structure of Calamites, Prof. Williamson makes the following remark :'—‘“ I am disposed to regard all existing specific names and definitions as worthless. They separate things that I believe to be identical, and confound others that are obviously distinct.” The specimen described below affords an interesting example in support of this view. Sternberg founded the species undulatus on specimens with undu- lating ribs, which he figured in the “ Flora der Vorwelt.”* In the « Prodrome d’une Histoire des végétaux fossiles,” Brongniart includes this species in his list of Calamites. 'The same author describes C. undulatus in his later work,* but suggests, however, that it may be a variety of Calamites Suckowit. Kttingshausen* recognizes the impossibility of separating the different species of Calamites, and includes Calamites undulatus, C. Suckowii, C. equalis, and many others under one species, C. communis. Schimper ° considers the flexuous character of the ribs and furrows of Calamites to be due*to vertical pressure, and attaches no specific importance to it. Dawson ° retains the species undulatus, because certain specimens show the reticulate markings on the surface similar to those repre- sented in Brongniart’s figures; the undulating character of the ribs he considers may perhaps be an indication of vertical pressure. Mr. Kidston’ does not include the species in his catalogue; he 1 Phil. Trans. Royal Soc. 1881, On the Organization of Fossil Plants of the Coal-measures, pt. i. Calamites, p. 507. 2 Versuch einer Geognostisch-botanischen, Darstellungen der Flora der Vorwelt. vers. i. p. 47, pl. i. fig. i. pl. xx. fig. 8. 3 Hist. des vegét. fossiles, tome i. p. 127. * Die Steinkohlenflora yon Radnitz in Béhmen, Abhandlungen der Kais. Konig- lichen Geologischen Reichsanstalt, ii. Band, 3 Abth. No. 3, p. 26. ° Traité de Paléontologie végétale, tome i. p. 313. 6 Report on the Fossil Plants of the Lower Carboniferous and Millstone Grit Formations of Canada, Geol. Survey of Canada, p. 30. 7 Catalogue of the Paleozoic Plants in the British Museum, p. 25. DECADE III.—VOL. Y.—NO. VII. 19 290 A. OC. Seward—Calamites undulatus. regards the flexuous character of the furrows to have been imparted by pressure, any Calamite being liable to a bending of its furrows from the same cause. The specimen now described and figured (Plate IX. Fig. 1. A. B.) is a pyritous sandstone cast of the medullary cavity of a Calamite, showing two internodes and one node. I found it in a piece of rock which had been brought to the surface in sinking a shaft at a colliery near Wigan. Figures 1 A, and 1 B. are opposite sides of the same specimen. In Fig. 1A, the ribs are perfectly straight and close together. No “‘infra- nodal canals” are visible on either side of the specimen. At the left- hand upper corner of Fig. 1 A, the ribs become wide and irregular : in Fig. 1 B, these characters are still further developed, the ribs and furrows now having a decidedly flexuous appearance. In Fig. 1 A, there are about eight ribs in a space of one cm., in Fig. 1 B, three occupy the same space. The length of the specimen is different on the two sides, the side with the straight ribs and furrows being 10cm. long, and that with the flexuous ribs 9cm. The ribs and furrows alternate at the node. On many of the ribs there is a faint median line visible, which is in some parts rendered more conspicuous by the presence of carbon- aceous matter. This difference in the breadth of the ribs on the two halves of the specimen is probably due to the original arrange- ment of the vascular wedges and medullary rays in the living Calamite. Prof. Williamson’ has figured a transverse section of a Calamite in which the distance between the woody wedges varies in the two halves of the stem, the medullary rays being narrow in the one half and wide in the other half of the section. In Prof. Williamson’s collection of microscopic slides, which I have had an opportunity of examining through his kindness, I have met with other specimens showing the same inequality in the size of the medullary rays on the opposite sides of the section. In the Woodwardian Museum there is a flattened cast of the medullary cavity of a Calamite which shows the same characters still more clearly (Pl. IX. Fig. 2 A, B). The specimen is 18 cm. long and 6:5 cm. broad. On the side shown in Fig. 2 A, the ribs are straight and close together; on the side shown in Fig. 2 B, they are wide and flexuous. ‘“Infranodal canals” are clearly shown on the side with wide and wavy ribs, but less distinctly on the opposite side. The following measurements show that the internodes on the side with the wide and flexuous ribs are shorter than those with the narrow and straight ribs :— (Plate IX.) Fig. 2 A. Fig. 2 B. (Number of ribs per cm. 35.) (Number of ribs per cm. 17.) Length of internode i. 3-9 cm. Length of internode i. 3°5 cm. * 0 li. 4 cm. a Be ii. 3:7 cm. ae 3 iu. 4°2 cm. At . i, 3:0 cm. A ms iv. 3°9 cm. iN a lv. 3:7 cm. 1 Phil. Trans. Royal Soc. 1883, On the Organization of Fossil Plants of the Coal-measures, pt. xil. pl. 33, fig. 19. Prof. C. Lloyd Morgan—Elevation and Subsidence. 291 The first specimen described also showed that the shorter side was that on which the ribs were wide and flexuous. These facts suggest that the flexuous or undulating character of the ribs and furrows may have been induced by a pressure which acted on the living plant and caused it to bend; this would have the effect of widening and crumpling the ribs on the concave side of the bent plant. I].—ELevation anp SupstpENcE: A SvuGGESTION. By Professor C. Luoyp Morean, F.G.S., Of University College, Bristol. T is unnecessary for me to remind the readers of the GroLocicaL Magazine of the evidence for elevation and subsidence. For my present purpose it is sufficient to remind them that such elevation and subsidence has been attributed (1) to lateral pressure giving rise to long geo-anticlines and geo-synclines; (2) to expansion and contraction of the underlayers resulting from a rise or a fall of temperature ; and (8) to the loading and unloading of the areas of the earth’s crust affected. Apparent elevation and subsidence, which we may here neglect, may be due to arise or fall of the sea-level such as is dealt with by Prof. Hull in a recent communication to this MAGAZINE. (1.) There can be no doubt that the formation of long geo-clines under the influence of lateral pressure (whether produced by secular contraction, by the screwing of the earth’s crust suggested by George Darwin, or otherwise) is a factor in the upheaval and depression of the land. So far as my present purpose is concerned, however, it is only necessary to point out that during the formation of geo-clines under the influences of this lateral pressure there must be a tendency to lessen the vertical pressure on the underlayers beneath a geo- anticline and to increase the pressure on the underlayers beneath a geo-syncline. (2.) The effects of hydrothermal action on the solid underlayers of the earth’s crust would seem to be of two kinds with opposite tendencies. First there is the direct effect of heat with a tendency to expansion. Mr. Mellard Reade has lately (‘‘ Origin of Mountain Ranges ”’) insisted on the importance of this factor in the upheaval of the surface. Secondly, there are the metamorphic changes super- induced. The tendency of these is towards condensation or con- traction. Which tendency predominates? I doubt if this question can be answered @ priori. But we are taught that continued sedi- mentation involves a rise of the isogeotherms beneath the area in which sedimentation is taking place: and we know that there is abundant geological evidence that areas of sedimentation are also areas of subsidence. If, therefore, the changes in the solid under- layers which result from hydrothermal action take place pari passu with sedimentation, such evidence as we possess is in favour rather of contraction than expansion. Or if expansion does take place, its effects must be over-mastered by those of some opposing tendency or tendencies. Mr. Mellard Reade would indeed contend that the 292 Prof. C. Lloyd Morgan—Elevation and Subsidence. uplift manifests itself in the mountain-building at the close of sedi- mentation. It is difficult, however, to understand why the effects should be so long deferred. As a corollary from the rise of the isogeotherms beneath areas undergoing sedimentation, we have the depression of the isogeotherms beneath areas undergoing denudation. Here, therefore, cooling should produce contraction, and there should be subsidence. ‘This is not in accordance with observation. (3.) The intimate connection between subsidence and sedimenta- tion on the one hand and elevation and denudation on the other hand has often been insisted on. This connection may be regarded in two ways. Many geologists maintain that denudation is consequent upon upheaval, and that continued deposition is consequent upon (or is conditioned by) continued subsidence. ‘To others, however (and I count myself among the number), this mode of looking at the facts is not wholly satisfactory. They regard the uplift as in some way the direct result of the lightening of the load by denudation, and the subsidence as the direct result of the added load by sedimentation. (a) Those who hold the latter view would seem generally to attri- bute the elevation and subsidence to the mere weight of the material added to or removed from a flexible crust resting upon a fluid or viscous substratum. (b) Mr. O. Fisher has suggested (Proc. Camb. Phil. Soc. vol. vi. pt. 1) that water gas may be dissolved in molten rock just as carbonic anhydride may be dissolved in water. Applying Henry’s law of the absorption of gases, he considers that on the pressure being relieved from that required for saturation, vesicles of gas may separate from the solvent and may coalesce and rise through the magma expanding as they reach regions of diminished pressure. From this expansion an uplift of the overlying area would result. (c) Prof. Joseph Le Conte has suggested (Nature, vol. xxix. p. 213) that the principle of flotation comes into play. He assumes that the crust of continental areas is more conductive and therefore cools and thickens more rapidly than that of oceanic areas. Thus inequalities of thickness of the crust would result, and by flotation these in- equalities, produced in this way on the under side next the liquid substratum, would be reproduced on the upper side next the atmosphere. Whether such flotation would take place depends upon whether the solid produced by cooling is heavier or lighter than the liquid from which it is derived and on which it rests. Now, although there is a want of agreement as to the amount of contraction which rocks undergo on solidification and crystallization, it is well nigh universally admitted that solidification does involve such contraction and increase of density. The thickened area would therefore tend to subside rather than to be upheaved. (d) It is the object of this paper to suggest other ways in which the loading and unloading of the earth’s crust may indirectly bring about subsidence and elevation. I must, however, first ask and seek to answer one or two preliminary questions. Prof. C. Lloyd Morgan—Elevation and Subsidence. 293 May we assume the existence of a fluid underlayer beneath the superficial crust of the earth? I think we may. From this source volcanic rock would seem to be derived ; and in the plutonic rocks we seem to see the solidified crust of the once deeply-buried under- layer. Whether the fluid underlayer be continuous or in more or less isolated reservoirs we cannot say. I shall suggest in the sequel a reason why this substratum should assume the fluid or viscous state. At what depth beneath the surface of the earth may the plutonic rocks have solidified ? It is well known that Mr. Sorby from the micro- scopical study of the contained erystals concluded that the granites of Cornwall solidified under a pressure equivalent to that of about 50,000 feet (94 miles) of rock, and that those of the Highlands indicate one of about 76,000 feet; while Mr. Clifton Ward suggested for the granite and granitoid rocks of Westmoreland and Cumberland a mean pressure of 44,000 feet of overload. Commenting upon these results Mr. Prestwich asks, “Are we warranted in supposing that there has been denudation to the extent of removing such enormous masses of rock as this would imply?” and Mr. A. Geikie answers, “Tt is not probable that any such thick overlying mass ever did cover the granite.” (Prestwich, Geology, vol. i. p. 432; Geikie, Text Book, p. 297.) What was the condition of the potential granite previous to solidification? Nearly all agree that it was rather from hydro- thermal solution (at a temperature of, say, 500° C.) than from igneous fusion that the rock solidified. As was long ago pointed out by Bischof, the thinness of the granite veins which branch out into clay slate, the sharpness of the line of junction between the material of the vein and that of the country, and the slight alteration the slate has undergone, point to the mobility of the fluid and render the possibility of gradual solidification from igneous fusion out of the question. (Chem. and Phys. Geol., Paul’s Translation, 1859, vol. iii. p. 52.) What is the amount of expansion under solidification ? Bischof’s experiments led him to believe that the formation of granite from a liquid magma involved a contraction of 25 per cent. Delesse gave from 8 to 7 per cent. as a more probable estimate. Mr. Mallet found a smaller amount of contraction. In the solidification of plate-glass the contraction was 1:59 per cent. In the case of iron- slag the diminution of volume was 6-7 per cent. Now the sp. gr. of obsidian is from 2:4 to 2°5, while that of granite is (say) 2°65, and that of syenite (say) 2-8. This would seem to point to a diminution of volume by 6 or 8 per cent. on passing from the vitreous to the erystallized condition, Probably therefore a diminution of volume by from 6 to 10 per cent. on passing from the molten to the crystal- lized condition may fairly be assumed to occur. It is well known that water expands when it passes into the con- dition of ice: that ice, say, at —1° C., subjected to pressure melts or is squeezed into the liquid condition: that at high pressures water may remain liquid though the temperature fall several degrees below 294 Prof. O. Lloyd Morgan—Elevation and Subsidence. zero: and that on relief of pressure such liquid expands into ice. Conversely Amagat has shown (Comtes Rendus, vol. 105, p. 165), that the solidifying point of carbon tetrachloride (a substance that contracts on solidification) may be raised from —19-5° C. to + 19-5°C. by increasing the pressure from 210 to 1160 atmospheres (approxi- mately). I would suggest that similar changes must occur as the fluid or viscous matter in the liquid substratum is subjected to increased or diminished pressure. Increased pressure would thus tend to squeeze the magma into the solid condition or to induce crystallisation therein. Diminished pressure would tend to allow the partially solidified or crystallized magma to expand into the fluid state. Take the case of an area undergoing continuous sedimentation. I would suggest that the increased load must tend to squeeze the magma in the underlayers into the solid condition. But in the solid con- dition the rock occupies less space. Contraction must take place and the contraction is manifested at the surface as subsidence. Further- more, without committing myself to the acceptance of the theory held by those who attribute subsidence to mere weight, I would suggest to the upholders of that theory that the added weight of the sediment above would entail on this hypothesis an added weight below—that is, if we suppose that the solidified rock adheres to the lower surface of the crust in this region. In a region undergoing denudation, on the other hand, the lighten- ing of the load would entail the melting of some of the solidified or crystallized magma. Such melting would be accompanied by expan- sion, manifesting itself at the surface by an uplift. By the expansion of the melting underlayers tensile stress in the overlying strata would be called into play, and this would throw these strata into a state of tensile strain, thus giving origin to normal faults (to account for the formation of which tensile stress must on any theory be called into play), to the gradual gaping of mineral veins, and to dykes into which the molten matter would be injected by the expansive force. Without denying as a factor that secular refrigeration on which Mr. Prestwich relies (Geology, vol. ii. p. 216), I would suggest that we have on this hypothesis an efficient primary cause of volcanic eruptions. In this way lava is pressed upwards towards the surface. The expansion of the contained water vapour does the rest of the business. It is clear that the process I have here suggested would be partially checked on the one hand by the assumed rise of the isogeotherms beneath the subsiding area, such rise, primarily due to sedimentation, being increased by the latent heat rendered sensible during solidifi- cation; and on the other hand by the converse depression of the isogeotherms and rendering latent of the heat of fusion beneath areas of denudation. In the area of subsidence lateral pressure would to some extent be brought to bear in aid of vertical pressure ; for it is evident that such subsidence is equivalent to the flattening of a portion of the Prof. 0. Lloyd Morgan—Elevation and Subsidence. 295 (approximately) spherical crust; and such flattening involves com- pression. On the view here suggested the earth’s crust, instead of being eaten into from below beneath the area of sedimentation, is there relatively thickened; while beneath continental areas of denudation, instead of being thickened, it is eaten into from below. The occur- rence of volcanoes on areas of elevation seems rather to lend support to the thinning of the crust in such areas, to its being rent by the stress so as to give rise to volcanic fissures, and, as in America, to fissure eruptions. Mountains on the Uinta and Park types of flexure (Geikie, Text Book,pp. 914-15) are iv accordance with this hypothesis. Concerning mountain ranges of the Jura and Alpine type, where lateral pressure has come so largely into play, I here say nothing. I believe, however, that the principle I am advocating may throw a little ray of light on that most difficult subject. It may be objected, however, that since liquids transmit pressure equally in all directions, there is no reason why the results of that pressure should be manifested immediately beneath the loaded area. But does not this depend upon the mobility of the liquid? The less mobile the liquid, the greater the tendency for the effects of loading to be concentrated beneath the loaded area. Beneath an area of sedimentation the mobility is much decreased by incipient crystalliza- tion. Moreover, we are ignorant how far the liquid substratum is continuous, and how far in disconnected reservoirs. ‘The objection may be more serious than I imagine. I should be glad of the opinion of physicists on this head. There is another way in which variations of pressure due to the loading and unloading of different areas of the earth’s crust may affect the liquid substratum. There can be little doubt that the water contained in the magma is above its critical temperature. Unless, therefore, it is dissolved in the molten rock, as Mr. O. Fisher has suggested, it must be in the state of compressed gas. But such a gas would expand and contract under variations of this pressure. Even if the temperature be not above the critical point, it must be near that point; and the recent researches of Ramsay and Young (Phil. Trans. 1886, pt. i. p. 123; 1887 (vol. 178), pp. 57 and 318), afford ample confirmation of the fact, first observed in 1835 by Thilorier in the case of carbonic anhydride, that near the critical point a substance in the liquid state is even more compressible than in the gaseous state above that temperature. To sum up. If the upper layers are by lateral pressure thrown into long geo-clines, there will be from this cause an increased pres- sure beneath the geo-synclines, and a diminished pressure beneath the geo-anticlines. The pressure on the geo-synclinal area will be increased by sedimentation, while that on the geo-anticlinal area will be diminished by denudation. This increased pressure beneath the area of sedimentation may, it is suggested, squeeze some of the underlying magma into a solid state, thus giving rise to contraction and further subsidence. It may also cause the further compression of the water gas contained in the magma, thus giving rise to further 296 Prof. C. Lloyd Morgan—Elevation and Subsidence. contraction and yet further subsidence. Conversely beneath an area of denudation the decreased pressure may allow some of the solidi- fied magma (kept solid by pressure) to liquefy, thus giving rise to expansion and uplift. It may also permit the expansion of the water gas contained in the magma, and thus give rise to further expansion and uplift. And if, as some geologists have contended, loading and unloading are in themselves sufficient directly to depress or to cause the uplift of a flexible crust, it is clear that subsidence will more readily take place in that area which is not only being loaded above, but is being also thickened below by the condensation of the magma into solid; and that uplift will be more readily effected where the crust is not only being denuded above, but being eaten into by the melting of the underlayers below. May we not perhaps account on somewhat similar principles for the existence of the underlying liquid or viscous substratum? Mr. Mellard Reade and Mr. Davison have lately independently pointed out that, owing to the cooling and contraction of the earth’s crust, there is at some depth beneath the surface a level of no stress, where there is neither lateral compression nor extension, though the rocks are of course subject to the vertical pressure of the overload. Above this level the rocks are subject to compressive stress, and below this level to tensile stress. Picture the earth as composed, onion-fashion, of a number of concentric shells, and fix the attention on one of these shells at a depth of say three miles from the surface. Suppose this shell to be cooling and undergoing contraction. The shrinkage thus brought about will throw the shell into a state of tensile strain (like the oft-washed flannel shirt which has become uncomfortably tight). Now transfer the attention to the fact that the shells in- terior to the one we have selected are contracting. The shell has to fit a continually diminishing nucleus (like the frock-coat of a man who is rapidly losing flesh). In accommodating itself to this shrinking nucleus, the shell is subject to compressive stress. The question is, then, with regard to any given shell, Which tendency predominates—the compressive stress due to the radial contraction of the sphere, or the tensile stress due to the circumferential con- traction of the zone in question? At the level of no stress these tendencies are equal and opposite: above that level compressive stress predominates: below that level tensile stress predominates. According to Mr. Davison (Phil. Trans. 1887) the level of no stress lies five miles deep from the surface; according to Mr. Mellard Reade (Origin of Mountain Ranges, p. 125), it may be taken to lie ata depth of one mile: Mr. Osmond Fisher would reduce this to less than a mile (Phil. Mag. Jan. 1888). Is it not possible, I would suggest, that throughout the zone of maximum tension, due to circumferential contraction, the rocks may be rendered fluid by relief of pressure ? I have now sketched out in briefest possible outline the suggestion or suggestions I have to offer with regard to elevation and sub- sidence. I have introduced no calculations of the amounts of upheaval or subsidence. Although it is easy to see that the accumu- Prof. T. G. Bonney—On the Ightham Stone. 297 lation of 12000 feet of Coal-measures in South Wales would involve a very material increase of pressure on the underlayers, | am of opinion that numerical calculations in these matters are only too apt to mislead by throwing a glamour of apparent mathematical accuracy over problems concerning which the most noteworthy feature is our profound ignorance. As in so many questions connected with the physics of the earth’s crust our data here are too scanty and too indefinite to make numerical calculations of much value. Who shall presume to assign quantitative shares (-+ or —) to (1) contraction due to metamorphism in the solid underlayers; (2) expansion of the rocks under increment of temperature; (38) the formation of geo-clines by lateral pressure; (4) contraction and expansion on melting and solidification ; (5) the effects of pressure on the water gas contained in the fluid magma; (6) the differential load on a flexible erust ? I for one will not. It is presumption enough in me to have ventured at all among the cross-currents of so difficult a sea, where to steer a mathematical course is impossible, and the best one can hope for is to keep one’s craft afloat. III].—Nore on THE StRucTURE OF THE IGHTHAM STONE. By Pror. T. G. Bonney, D.Se., LL.D., F.R.S., F.G.S. OME time since a student of University College, Mr. J. Hale, of Ivy Hatch, brought to me specimens of an extremely hard green sandstone, which he informed me came from the Folkestone Sand stage near Ightham, in Kent. As the microscopic structure proved rather interesting, I lately visited the locality in his company, and had the additional advantage of being conducted by Mr. B. Harrison, of Ightham, so well known for his discoveries of palzo- lithic implements and for his minute knowledge of the geology of the neighbourhood. The rock is briefly noticed in Mr. Topley’s excellent Survey Memoir on the Geology of the Weald, in the following terms (p. 140) :—“ At Ightham, near the Roman Camp, is a hard white sand- stone five feet thick, a good deal like the ‘ Greywether’ sandstone of the Tertiary, and there is too another kind of stone, not observed elsewhere, a hard and tough dark green sandstone or rather grit. This was not seen in place, but on Ightham Common it is found in large masses, and is there called Ightham Stone and sometimes Fire- stone, from its being sufficiently hard to strike fire well.” The white sandstone is well exposed at the top of the northern escarpment of the commanding elevation of Oldbury Hill, and its cragey outcrop forms a part of the defence of the ancient camp. The rock appeared to me to vary in thickness and to be somewhat lenticular in its mode of occurrence.! Beneath the camp it is under- lain by soft ferruginous sand, but a short distance to the south and a few feet below, another mass of sandstone crops out, which how- ever is not nearly so hard. This seems to increase rapidly in thick- ness, and to be soon full ten feet thick, and perhaps more. On the 1 Mr. Harrison informs me it is about 140 feet above the top of the Kentish Rag. 298 Prof. T. G. Bonney—On the Ightham Stone. south-eastern side of a little combe we again find the hard white sand- stone, capping a spur of the hill, and about three yards below it the softer bed crops out. I have examined microscopically the hard bed, which recalled to my mind, before I had read the passage quoted above, some of the hardest ‘greywethers.’ It consists almost wholly of fairly angular to subangular quartz grains, commonly about 0125” in diameter, which are probably derived from some granitoid rock, but do not exhibit any minor peculiarities worthy of remark. These are cemented by secondary quartz, in no great quantity, which is sometimes, but not always, in perfect optical continuity with the original grains, which often appear enclosed by coloured rings when viewed with crossed Nicols; probably from causes similar to that which produces them in separate grains and chips. There are a few grains showing a minute chalcedonic structure and one or two of brown or nearly black iron oxide. Parts of the slide also have a rather dirty look—in short, the rock is very like one of the hard grits or less perfect quartzites that one finds among the older Paleozoic rocks. The other rock mentioned above is peculiar. It is of a glaucous green colour, varying somewhat in depth, and it weathers on the outside to a rusty brown. This suggests that the tint is due toa silicate of iron, and in the process of weathering the cementing mineral appears to be partially removed ; for the discoloured portion, often an inch or so in depth, is less solid than the rest of the rock. Occasionally a smooth face of a fragment—probably an old divisional surface—has a kind of glazing of the green-coloured substance. The stone probably occurs én situ ata slightly higher level in the Folkestone Sands (here about 100 feet thick) than the white rock, for shallow pits have been dug in search of it over the upper part of Oldbury Hill! Boulders also were formerly abundant over the surface in many places, resulting from past denudation. Some also, like erratics, as Mr. Harrison informed me, have been transported northward and eastward for more than a mile, and may be found lying on the lowland of Gault almost as far as the base of the escarpment of the North Downs.’ The mode of working for the masses of green rock suggests that, like the Sarsen-stones of the Tertiary and the Cornstones of older rocks, they are of concretionary origin. The rock is not generally seen in situ, but Mr. Hale took me to a sandpit where two masses were exposed. The opening was some 20 feet deep. In the lower part the sand was markedly false-bedded, being in the upper fairly horizontal, with alternating coarser and finer bands of white, pale red, or brownish colour. Toa depth of perhaps a couple of yards . the usual flagey masses of sand cemented by limonite were common. The two blocks of green ‘quartzite’ were nearly on the same level, 1 Mr. Harrison informs me that when the rock was extensively worked for the Metropolitan roads, some half-century since, it always occurred in detached masses, is that the opener of a pit might get sometimes nothing, sometimes a rich return, for S pains. 2 The surface of the ground at the Camp is from about 500 to 600 feet, of the Gault about 300 feet above the sea. Prof. T. G. Bonney—On the Ightham Stone. 299 one being rather less than a foot in thickness, the other perhaps about six inches,! and well-defined bands of ironstone extended for a foot or so below them. Beneath them consolidated sand was rare or absent. The relation of these masses to the surrounding sand left no doubt in my mind that they were of concretionary origin ; the sand being cemented by deposition of secondary silica. When examined with the microscope the green rock is found to consist almost entirely of grains of quartz, often about :02” or 025” diameter, which for the most part are remarkably well rounded. These contain, in variable number, cavities, generally very small and commonly empty, and occasional microlithic enclosures, such as hair-like belonites, brownish-olive films(mica or in some cases tourma- line ?), and occasionally zircon. One grain also contains a number of yellowish-brown needles about 005” long. The general aspect of these grains leads me to conclude that they have been derived from a granitoid rock. With them occur a few grains of a chert (perhaps not generally so well rounded) varying in colour from brown to colourless, and sometimes apparently containing fragments of organisms. Rounded grains of limonite also occur as is common in the Folkestone Sand. There are also a few fragments distinctly — of organic origin, presently to be described. The cementing material is chalcedonic quartz, the tiny crystals commonly growing outwards from each sand-grain, like a fringe, having a moderately distinct radial arrangement. The surfaces of adjacent grains are rarely quite in contact, but even at the nearest parts are separated by a thin Felix Oswald dol. Ightham Stone x 35. film of microcrystalline silica. Now and then an interspace between the fringes is occupied by chalcedonic silica, confusedly arranged, or more rarely by limonite, which probably is associated with silica. Occasionally brown films may be noticed in the quartz grains them- selves, as though the limonite had made its way into cracks. The ? From their position in the scarped face of the sand, they could not be reached for measurement without an amount of trouble that would have been wasted. 300 C. EF. De Rance—Age of Clwydian Caves. lighter varieties of the rock exhibit under the microscope no indica- tion of the colouring matter, except, perhaps, that the boundary of grains appears somewhat more definitely marked than is usual in a colourless quartzite, but in some of the darker specimens a thin greenish-coloured film can be detected round each grain, and the same tint is disseminated through the microcrystalline ‘cement.’ It would appear then that the first stage of consolidation was the deposit of a film of iron-silicate, minute quantities of which were from time to time precipitated during the formation of the chalcedonic quartz. The figure represents, somewhat diagrammatically, the general structure of the rock, omitting the organisms and darker grains. The fragmentary organisms contained in this rock are not very common. Those which I have noticed are not much larger than the sand grains, and are often somewhat cylindrical in form. They can be readily detected with a good lens. With the exception of a few which resemble Annelid tubes, but may possibly be inorganic, they are of a pale green colour, and appear to have a slightly roughened surface, one or two much resembling bits of small spines of an KEchinid. When seen under the microscope, they exhibit a peculiar reticulate structure, dark in colour, with the interspaces occupied by microcrystalline silica. I have no doubt they are really from an Kchinid, some being probably bits of the test, while others are from the spines. One slide gives a very good transverse section of a spine about 14” in diameter.! I note also a longitudinal section of a moderately elongated spiral Gasteropod, about °25” long, with one or two other fragments, of the nature of which I am doubtful. So far as I am aware this conversion of asandstone into a quartzite by the deposition of chalcedonic silica is rare among the older rocks. In my own researches I have never come across a case, but Prof. R. D. Irvine mentions its occurrence among the older American quartzites, and figures an example from a cherty Potsdam sandstone from Wisconsin.? It occurs also in the ‘Sarsen stones’ and in the matrix of the Hertfordshire ‘Puddingstone,’ but in all these cases (so far as I know) the growth of the chalcedonic silica is much less regular than in the rock which I have described. But after I had examined the above described specimens, Miss C. A. Raisin, who at my request had undertaken the investigation of a parcel of rocks from Somali-land, found a very similar case, which will be noticed in the account which she is preparing. IV.—AGE oF THE CiwypIAN CAVES. By C. E. De Rancz, F.G.S., A.I.C.E. he following abstracts of early papers, on the Cefn Caves, throw a most interesting light on the sequence and method of occur- rence of the deposits found at the Tremeirchion Caves, which are 1 T have to thank Dr. G. J. Hinde for specimens for comparison. The genera Pseudodiadema and Peltastes seem to be most common in the Upper Neocomian rocks of England. So far as I can judge, I should refer these spines to the former genus. 2 Fifth Annual Report of the U.S. Geol. Survey, plate xxxi. C. E. De Rance—Age of Clvydian Caves. 301 four miles east-north-east of them, and on the opposite side of the Hlwy and Clwyd valley. In February, 1832, the Rev. Edward Stanley, afterwards Bishop of Norwich,! visited the Cefn Cave, and found the bones of animals, stags’ horns, and a human skull pierced with some sharp implement ; he was then shown a new cave, about 100 feet above the lower one, and about 40 or 50 feet below the summit; it was discovered in cutting new walks on the hill-side constructed by the owner, Edward Lloyd, Esq.; he found the new cave to have two distinct entrances, the western being full of bone-earth made of comminuted fragments of bone, with numerous large bones of animals, crushed apparently by hyzenas, whose teeth were found to be numerous. The cave could then be followed a distance of about 80 feet, with a varying height of six to ten feet; the top portion was clear of material, but he considered that the mass of drift formerly “ filled up every cranny and fissure to the very roof.” From this examination and another made on the 4th of April, he found the beds to consist ‘“ of fine loam, or clay of an ochrey colour and calcareous nature, readily effervescing with acids; generally speaking, the mass is deposited in horizontal lamine, portions of which may be readily detached, but broken in upon, without order or regularity, by pieces of limestone, which, from their position and angular form, have evidently fallen from the roof. Bones were numerous, and broken pieces of hazel or birch occurred.” ? Mr. J. E. Bowman ®* carried his examination 25 feet beyond that of Dr. Stanley ; he found the surface of the drift to be 18 inches beneath the roof of ‘the cavern ” (upper cavern of Stanley); he infers from the trough-shaped entrance, and from the presence of sand and gravel in the cavern, that “‘the cave must have been a watercourse.” He found the section to be as follows :— 1. Innumerable laminz of impalpable mud or silt, alternating reddish (effervescing) bands, and pale ochreous layers that do not effervesce 1’:6” to 2:0”. 2. Marl or clay with angular limestone, and water-worn pebbles, with bones and teeth a little way from the top, increasing downwards into a pure bone-earth, containing Hyznas, Rhinoceros, etc., about two feet. 3. Compact “ diluvium of clay,” with pebbles of clay-slates, and a few splintered bones, and stalactites, two feet. 4. Coarse and fine sand, loam, and clay, no bones, pebbles, or shells, three feet. Mr. Joshua Trimmer,‘ in 1838, describes in a paper published in full in 1841,° the Cefn Cave as occurring at the point in which the erratic gravel of the eastern and northern side of the Cambrian passes into the district Overspread with detritus from Cumberland ; 1 Father of Dr. Stanley, Dean of Wermuneter. 2 Edinburgh New Phil. Journ. yol. xiv. p, 40-53 ; Proc. Geol. Soc. London, vol. i. p. 402 (abstract). 3 J. KE. Bowman, Cefn Bone Caves, Brit. Assoc. 1836. 4 Trimmer, Cefn Bone Caves, Brit. Assoc. Report for 1838, London, 1839. 5 Practical Geology and Mineralogy, London, John W. Parker, West Strand, 1841, p. 400, etc. 302 C. E. De Rance—Age of Clwydian Caves. in a gorge of the Elwy, a little above its junction with the Clwyd, its mouth being 100 feet above the river and 200 feet above the sea; the cavern, he states, communicates with the surface by fissures, which, like the surface, are occupied by Northern Drift. Sedimentary deposits containing bones and teeth of Hyena, Bear, and Rhinoceros, filled the cavern mostly to the roof; these were divided into two beds by a crust of stalagmite; the lower bed, he states, ‘was below the level of the entrance from the face of the cliff, and contains bones and teeth enveloped in sediment, and mixed with smooth pebbles like those of the adjacent river, and fragments of wood.” Above the stalaemite the upper bed consisted of “calcareous loam contain- ing bones and angular fragments of limestone, on the surface of which,” he stated, ‘“‘are sand and marl containing fragments of marine shells like those dispersed over the neighbouring district. The sediment within the cave is generally finely laminated.” The author points out that the lower bed must have been derived from the river, when it flowed at a different level; he states that marks of teeth on the bones prove the cave to have been the home of carnivora, and that it was subaerial for some time, allowing the stalagmite to form, and states, that Dr. Traill noticed that the laminz of the overlying deposit conform to the dip of the limestone, and attributes this also to fluviatile action, subsequent to the marine irruption from above. Mr. Trimmer illustrates bis remarks by the following section : a. Level of the entrance of the cave. b. Deposit of mud, covered by stalagmite and containing bones, with rounded pebbles of grauwacke and limestone and pieces of wood. c. Mud, bones, and angular fragments of limestone. d. Sand and silt, with fragments of marine shells. e. A fissure communicating with the surface. Ff. Northern drift spread over the surface of the country. g. Portion of the cave cleared of mud. h. River Elwy, 100 feet below the cave. z. Limestone rock, In 1863 the “Geologist”! states that bones in the possession of Colonel Watkin Wynn, discovered in the Cefn Cave, were examined and named by Dr. Falconer, and found to belong to 1 Geologist, vol. vi. p. 114, 1863. J. V. Elsden—Igneous Rocks of Lleyn, N. Wales. 308 Elephas antiquus, Rhinoceros hemitechus, Rhinoceros tichorhinus, Hip- popotamus major, Bos sp., Cervus sp., and others, and states that Dr. Falconer and Professor (now Sir Andrew) Ramsay together dis- covered fragments of Cockles and other marine shells in the clay, and amongst gravel and stones, with which the cave is filled.' Sir Andrew Ramsay himself refers? to this discovery, and states that the Cefn caves ‘“‘ were below the sea during part of the Glacial Epoch, for the Boulder-clay beds reach a higher level, and with Dr. Falconer I found fragments of marine shells in the cave overlying the detritus that held the bones of elephants and other mammalia.” No reference is made by Dr. Buckland, in the “ Reliquize Diluviane,” to the Cefn Cave, but he quotes Pennant as to the discovery of two molar teeth and tusk of Mammoth at Halkin Mine at the mouth of the Vale of Clwyd, which was probably the Talargoch Mine, of which Dr. Buckland gives the following section :— Yds. Ft Weretable;monldyyiecpecccnenst--c0sssers- 0 2 Clay Ne ccs tae 26 0 Mand ands Gravel acess cssemcesesssscsseccene 68 0 He states that pebbles of lead and some pebbles of copper occurred in the gravel, and that horns, teeth, and bones of Mammals occurred at from 40 to 70 yards from the surface, and also in the bottom bed resting on the subjacent rock. Mr. Mackintosh* found the “sand with minute fragments of sea shells, still adhering to. one side, of a rising branch” of the cavern “ascended by steps.” On the 22nd of May last Mr. Bouverie Luxmoore, F.G.S., and the writer, found this bed still visible, fragments of Tellina Balthica being determinable. From these observations it is obvious that the bones discovered belonged to Mammals, who lived before the filling up of the Vale of Clwyd, and the sealing of its cavern by Glacial Drift. V.—Norres on THE JGNEOUS Rocks or THE Luryn Promontory. By J. Vincenr Exspen, B.Sc. (Lond.), F.C.S. jee of the rocks of this district have been already described by the late Mr. Hi. B. Tawney, in a series of papers entitled * Woodwardian Laboratory Notes,” contributed to the GronogicaL MacazineE a few years ago. The following additional remarks are to a certain extent supplemental to the above-mentioned papers, and are founded on a microscopical examination of a large series of rocks, collected some few years ago during a brief visit to the Lleyn district. Commencing at the extreme end of the promontory, we find around Aberdaron three or four masses of intrusive rock, which are described in Mr. Tawney’s paper as diabase, containing plagioclase often full of greenish microlites, augites in small quantity, of corroded outline and much altered into viridite, and a large quantity of black iron- 1 Dr. Murchison states Dr. Falconer’s visit was in August, 1859. 2 Physical Geology and Geography of Great Britain, p. 462, 5th edition, 3 Q.J.G.S., 1876. 304 J. V. Elsden—Igneous Rocks of Lleyn, N. Wales. oxide, both magnetite and ilmenite.1 His specimens were selected from Pen-y-cil, Aberdaron quarry and Tynrhedyn, S. of Llanfaelrhys, and to his description of these rocks I find nothing to add, with the exception that one of my rocks taken from Pen-y-dre, close to Aberdaron, contains a much larger quantity of augite, in well-defined crystals. The small isolated patches, lying to the North of Aberdaron, and coloured as serpentine on the Survey map, are not described in Mr. Tawney’s paper. I obtained specimens of these so-called serpentines from Hendrefor, Ty-hen and Methlan. The rock from the last- mentioned locality appears under the microscope to consist of a net- work of plagioclase crystals, sometimes polarising brilliantly, but generally clouded with minute enclosures and decomposition pro- ducts. The felspars are seen penetrating plates of augite, with brilliant polarisation colours. ‘The whole rock is traversed by veins of serpentinous substance, and there are many patches of viridite. Biotite is sparingly represented and probably of secondary origin. Titaniferous iron, mostly decomposed into leucoxene, is present, and some bronze crystals of pyrite are seen by reflected light. Although there is far more serpentinous and viriditic matter than in the rocks of Aberdaron, iron separation has been less extensive. The specimen from Ty-hen is finer-grained, and the felspars much more decomposed. The interspaces are chiefly filled with green fibrous viridite, with aggregate polarisation. ‘'There is but little fresh augite, and a good deal of titaniferous iron generally altered into grey opaque leucoxene. Some threads of serpentinous substance also occur, and a little secondary biotite. ‘Two specimens taken from the extreme margins of these small bosses are interesting examples of contact metamorphism. The felspar crystals become very minute, probably owing to more rapid consolidation, and portions of the sur- rounding sedimentary rock appear entangled in a confused way with the igneous matter. Macroscopically these rocks are greenish-looking and sufficiently soft and serpentinous to account for the Survey colouring. They do not differ much, however, from the diabases around Aberdaron, except in their more pronounced viriditic decomposition. We come now to the large mass of igneous rock extending from Mynydd Penarfynydd on the south to Mellteyrn on the north. The rocks of this area are especially interesting on account of their variety. Thus the western slopes of the Penarfynydd ridge, as shown by Mr. Tawney, are of olivine diabase, which he considered to be a dyke intrusive in the hornblendic diabase of which the rest of the ridge is composed. It must be mentioned also that Mr. Tawney was unsuccessful in his attempt to discover the locality from which Sedgwick procured his specimen of hornblende picrite in this vicinity. The specimens of hornblende diabase described in “‘ Woodwardian Laboratory Notes”? were taken one from Careg Llefain, and the other from near Plas Rhiw. — My first specimen, in connexion with this area, was taken from 1 GroLocicaL Magazine, 1880, Decade II. Vol. VII. p. 214. J. V. Elisden—Igneous Rocks of Lleyn, N. Wales. 305 the northern flank of Mynydd-y-Graig, about midway between these last-named localities. In this rock plagioclase is abundant, but rather decomposed. The extinction angle is rather large, corre- sponding to anorthite. Some crystals look like orthoclase twinned on the Carlsbad type, but are shown by their symmetrical extinction of about 53° to the trace of the twinning plane to be plagioclase. The augite is sometimes tolerably fresh, extinguishing perfectly, but other crystals show aggregate polarisation. It is often inter- penetrated by felspar, and the margins are developed into strongly dichroic brown hornblende. A brownish granular substance is often arranged in bands across the cleavage directions, and sometimes there are inclusions of hornblende. There is also a good deal of fibrous yellowish green viriditic substance, resulting probably from the decomposition of augite and hornblende. In one case lines of opaque granular decomposition product intersect at the characteristic prism angle of augite. At Treheli the same general characteristics are noticed. Under the microscope the plagioclase is seen to be abundant, but rather decomposed, Where polarisation colours are still given, the ex- tinctions are apparently not so high as in the last-mentioned speci- men. ‘The augite is also not so fresh: it occurs in irregular masses, often developed into hornblende. Some crystals have a central patch of decomposition product, giving aggregate polarisation, the margins extinguishing perfectly. In other cases the margins are decomposed and the centre fresh. Large masses of a clear pale yellow substance, with granular patches here and there, show between crossed Nicols a central dark patch, changing but little on rotation, surrounded by densely interlacing fibrous crystals, with brilliant ageregate polarisation and feebly pleochroic. ‘These fibrous, tufted crystals occur chiefly at the junction of hornblende and augite. The hornblende is much less altered than the augite, many of the viridite patches being fringed by perfectly fresh-looking hornblende. Original magnetite seems scarce, but lines of secondary oxide of iron often mark the boundaries of augite crystals, the interior being occupied by viridite. North of the road near Tyganol-bwlch-y-rhiw, we begin to approach the so-called Rhos Hirwaun syenite, and here the rock undergoes considerable change in character. The felspar is here very opaque, and often encloses green microliths. The augite seems to be nearly all converted into viridite, which is interpenetrated by the felspars. Even the apparently unaltered fragments give agere- gate polarisation. Quartz is fairly abundant in crystals and irregular grains, and generally contains enclosures of apatite needles, as well as cloudy patches of fluid and gas cavities. No hornblende can be detected; but there are a few ill-defined flakes of brown mica. There is a fair quantity of magnetite, and some ilmenite, partly converted into leucoxene. This rock appears to be a quartz-diahase, but a comparison would be interesting with the diabase of Castell Carron, about two miles north of this point, in which Tawney recog- nized quartz of secondary origin. DECADE III.—VOL. V.—NO. VII. 20 306 J. V. Elsden—Igneous Rocks of Lleyn, N. Wales. Immediately around Meyllteyrn we find the whole rock consist- ing of a network of felspar prisms, generally rather turbid, the interspaces being filled with augite in every stage of decomposition into viridite. In one specimen not a fragment of unaltered augite remains, while in others some crystals are still very fresh, polarising brilliantly and extinguishing perfectly. One large patch of viridite has at its two extreme ends two small portions of still unaltered augite, which extinguish simultaneously, as if originally portions of one and the same crystal. Magnetite is not very abundant, and generally of secondary origin, forming imperfect skeletons of augite crystals. There is a fair quantity of ilmenite, but much decomposed into leucoxene, and pyrites is sparingly present. It now remains, before leaving this tract of igneous rock, to men- tion the so-called Rhos Hirwaun syenite, which is mapped by the Survey as occurring in two isolated patches. It has been shown by Mr. Tawney that the boundaries of these patches are incorrectly mapped, for he describes specimens from Pen-y-gopa and Penllech (within the greenstone area) which should belong to the so-called syenite, while the rock of Clip-y-Cilfinhir is in reality a diabase.' The rock of Pen-y-gopa differs from that of Ty-mawr, described by Prof. Bonney,” in containing hornblende and but little mica, and is described as hornblendic gneiss. The specimen about to be described is taken from quite the other side of the main mass of this rock, from near Pen-y-bont, close to Llangwnadl. In the hand specimen this rock is an exceedingly tough fine-grained dark green hornblendic rock, traversed by fine veins of lighter green and speckled with small grains of quartz and felspar. Under the microscope the rock is seen to consist chiefly of dark greenish-brown hornblende, with characteristic cleavage and strongly dichroic where fresh, but the dichroism decreases rapidly with alteration, and it ultimately passes into a chloritic pseudomorph. The felspar is generally turbid, but here and there shows the characteristic twinning of plagioclase. Some orthoclase is also recognizable. The quartz is almost indis- tinguishable from the felspar except in polarised light, and is generally turbid with a multitude of minute cavities. A few crystals of magnetite and some pyrites are present. On the whole this rock bears a much closer resemblance to the Pen-y-gopa specimen than to that of Ty-mawr, but there seems to be scarcely sufficient trace of foliation to entitle it to be classed as hornblendic gneiss. Between Llanengan and Llangian are two small greenstone areas not touched in Mr. Tawney’s paper. At Pen-y-gaer quite half this rock appears to consist of felspar, but much decomposed. The felspars form a network, filled up by augite, which it also penetrates deeply. ‘The augite is brownish, with much iron separation along the cleavage cracks, and sometimes the whole crystal is rendered opaque from this cause. Scarcely any of the augite extinguishes 1 GrotocicaL Macazine, Vol. X. p. 68. 2 Q.J.G.S. vol. xxxv. p. 306. J. V. Elsden—LIgneous Rocks of Lleyn, N. Wales. 307 completely between crossed Nicols. There isa good deal of strongly dichroic hornblende, sometimes intergrown with the augite, at other times in detached crystals. It generally polarises more brilliantly and extinguishes more thoroughly than the augite. Viridite patches are abundant, and a little secondary quartz occurs. Most of the iron oxide shows the grey decomposition product of ilmenite, but some pyrites is to be noticed. The same rock near Llangian is much more decomposed, the felspars being quite opaque and much viridite and opaque ferric matter present. Some of the viridite tracks appear to have outlines of augite crystals; one looking like an orthodiagonal section gave an angle of 135°, which nearly corresponds to the angle between oo P and ow P®o (clinopinacoid) in augite. Small quartz fissures traverse the rock. We now pass to the large patch coloured as porphyry on the Survey Map, lying between Llanbedrog and Capel Ceidio. The southern portion of this area consists chiefly of quartz-felsite, and at Pig Street, Mr. Tawney described a volcanic ash. I find a coarse tuff on the south side of Mynydd Mynytho, and a similar kind of rock to the north of Madryn, at Y Gledrydd. My other specimens from this area do not differ essentially from those already described in Woodwardian Laboratory Notes." The Boduan mass of porphyrite is described from several localities in Mr. Tawney’s paper. J will only add one more description of a rock taken from the extreme south side, near the village of Boduan. The rock here is much decomposed; the ground-mass is micro- crystalline, consisting of small felspar prisms, which from the small extinction angle is possibly oligoclase. Precise determination of the larger felspars, which occur porphyritically, is difficult owing to decomposition, but no orthoclase can be recognized with certainty. There is some glassy base between the crystals. A few magnetite grains and a good deal of opaque ferric matter occur throughout. No trace of hornblende remains, although a few teebly dichroic chloritic pseudomorphs are to be seen. This rock differs, therefore, from that of Carn Boduan. Approaching Nevin the character of the rock changes considerably. I give a description of the rock near Nevin, which much resembles that described by Mr. Tawney as probably coming from Moel Gwyn, and which he classes as epidiorite. The large felspars are much decomposed, but are apparently triclinic: they are generally filled with a fine granular substance, and sometimes crowds of colourless microliths are visible with crossed Nicols. The ground-mass consists chiefly of quadrangular sections, with nearly parallel extinction, corresponding to oligoclase. Hornblende is present in detached crystals, which gradually lose their fibrous structure and dichroism and pass into chloritic pseudomorphs. A few remnants of augite are visible. Magnetite is abundantly associated with the decom- posing hornblende, and there are some opaque rhombohedral crystal of ilmenite. 1 GroLtocicaL Macazing, Vol. X. p. 70. _ 808 oS. V. Elsden—Igneous Rocks of Lleyn, N. Wales. We now come to the so-called serpentine of Porth Dinlleyn, described by Prof. Bonney in Q.J.G.S. vol. xxxvii. p. 48, and iden- tified as altered diabase-tuffs, decomposed diabases and basalts. His specimens were selected exclusively from the eastern side of the peninsula. I therefore proceed to the west side of the promontory. Near the ‘‘ Ancient Fortress” the rock appears to be a true diabase, and shows under the microscope a network of felspar, too clouded for determination of extinction angles. Strings of serpentinous matter and a good many viridite patches are scattered through the slide. Pale brownish augite occurs in small crystalline grains still polarising brilliantly. The opaque bodies are not abundant, and seem to consist entirely of magnetite and some pyrites. A little further south the rock is very similar to the above. About half the slide consists of prisms of felspar, sometimes polarising brilliantly, but generally decomposed. The extinctions are at a somewhat high angle to the trace of the twinning plane. Some of the felspars are porphyritic, with broken outlines. Augite is sparingly represented in detached grains and crystals, rather deeply coloured, and showing marked pleochroism. A good deal of greenish decomposition product occurs between the felspar crystals, and magnetite, ilmenite and some pyrites are scattered throughout. Apatite needles and a little biotite also occur here. Some of the felspars show a tendency to to saussuritic decomposition, giving aggregate polarisation, and greenish alteration products with some epidote. Still further south the rock becomes more serpentinous in appear- ance, and under the microscope more than half the slide is seen to consist of bright green serpentine, the remainder being an opaque, greyish substance, interpenetrated everywhere by serpentinous matter. Patches of calcite abound, and threads of the same mineral traverse the serpentine. Innumerable bands of dark granular matter, in more or less wavy parallel lines, occur throughout. These under higher powers transmit feeble brownish colours, and have the appearance of picotite. This is so far as I know the only instance of the occurrence of a rock approaching the character of true serpen- tine in Lleyn. The arrangement of the opaque bands is not such as to recall the “maschen structur” of peridotic serpentines, but possibly as my specimen was taken from the junction of the rock, we may have here the results of contact metamorphism of the sur- rounding schists. _ The greenstone dykes of Porth-wen appear to be chiefly dolerite, Under the microscope the rock appears to be crowded with lath- shaped crystals of felspar, no longer polarising in very bright colours. A good deal of viridite and some biotite are present. Olivine crystals are almost entirely altered, but are still recognizable. Augite also remains, but generally very opaque, from iron separation. A good deal of secondary calcite is seen, as well as magnetite and pyrites. R. Lydekker—WNote on the Ichthyopterygia. 309 VI.—Nore on run CLAssrricATION OF THE ICHTHYOPTERYGIA (WITH A Notice or Two New Sprcizs). By R. Lyprexxer, B.A., F.G.S., ete. |S levee devoted several weeks to the study of the magnificent collection of the remains of Ichthyopterygians preserved in the British Museum (Natural History), I purpose on this occasion to give a brief notice of some of the conclusions at which I have arrived, since a considerable interval will elapse before the publication of that part of the Museum “Catalogue of Fossil Reptilia” in which my observations will be more fully recorded. Exclusive of the genus Cetarthrosaurus, which is referred by Mr. Hulke to the Mosasauridea, four genera of Ichthyopterygia have hitherto been described; viz. Ophthalmosaurus, Seeley, Baptanodon (Sauran- odon), Marsh, Ichthyosaurus, Konig, and Mixosaurus, Baur. Since, however, there appear to be no characters by which Baptanodon can be generically separated from Ophthalmosaurus, I am inclined to follow the suggestion made by Dr. Baur, and unite the two; thus reducing the number of genera to three. With regard to Ichthyosaurus, it has been suggested by more than one writer that this genus is susceptible of division into two or more genera; and there is much to be said for this view, since there is an extraordinary amount of structural difference between many of the forms. If, however, the species be arranged in their natural relationship, which corresponds to a great extent with their distribution in time, it will be found that these distinctive characters tend to shade more or less completely into one another. Since, moreover, the skulls of all the species seem to be so nearly alike in general structure that it is very improbable that good generic characters could be drawn from them, I have come to the conclusion that it will be more convenient to the paleontologist, and most certainly to the pure geologist, to retain the genus in its original wide sense. I intentionally use the term convenient in this con- junction because I am glad to see that Prof. Flower,’ in his recently published memoir on the Liberian Hippopotamus, has expressed his opinion very clearly that the restriction or multiplication of generic terms is purely and simply a matter of convenience; and that their multiplication rather tends to make us lose sight of the mutual relationship of allied forms. I am further convinced of the advisa- bility of retaining the original use of the term Ichthyosaurus, because if we once begin to subdivide it, it will be almost impossible to know where to stop. Dr. Baur, who adopts the view of the advisability of splitting up the type genus, makes the three above-mentioned genera the types of three distinct families ; but if the term Ichthyosawrus be employed in the sense indicated above, it appears to me that the whole three genera may be conveniently included in asingle family—the Ichthyo- sauride. The last-mentioned writer has shown very clearly that while Ichthyosawrus occupies the middle position, Ophthalmosaurus is the 1 P.Z.8. 1887, p. 614. 310 R. Lydekker—Note on the Ichthyopterygia. most, and Mixosaurus the least, specialized genus; and I find that while among the Liassic species Ichthyosaurus communis in the structure of its limbs makes the nearest approach to Ophthalmosaurus, I. tenuirostris and its allies are the forms most nearly allied to Mixo- saurus. Now the pectoral limb of the generalized JI. tenwirostris having only four digits, while in the more specialized species the number is greatly increased, it may be inferred that Ichthyosaurs have descended from a tetradactylate ancestor, or at least that only four digits have been primarily modified into the Ichthyosaurian paddle. A comparison of the pectoral limb of I. tenuirostris with that of Chelydra has moreover led me to conclude that the four digits there found correspond to the 2nd, 3rd, 4th, and 5th of the typical manus ; the 3rd arising in the same way from the intermedium, and the 4th and 5th conjointly from the ulnare. The primary grouping of the genus which I have adopted is mainly based upon the simpler or more complex structure of the pectoral limb; and I may add that in those forms where the original four digits have become split up it is evident that the presence of two centralia in the carpus is an acquired and not an inherited character. ‘This classification is in the main a modification of the one proposed by A. Wagner, and subsequently extended by Col. Kiprijanoff in the Memoirs of the St. Petersburg Academy for 1881. It is briefly summarized in the following table, which contains a synopsis of all the named species with which I am acquainted. The specific names applied by Hawkins to several of the English Liassic species are, however, omitted. In cases where the generic position of species is uncertain a note of interrogation is placed after the generic name; and when the serial position is pro- visional an asterisk is prefixed :—- I. Genus Oputuatmosaurus, Seeley (Baptanodon = Sauranodon, Marsh).—Humerus articulating distally with three bones. 1. OPHTHALMOSAURUS ICENICUS, Seeley. Oxford and Kimeridge Clays, England. 2. OPHTHALMOSAURUS NaTANS (Marsh). Up. Jurassic, N. America. 3. piscus (Marsh). __,, + 4. i CANTABRIGIENSIS, N.Sp. noble Cambridge, Greensand. Il. Genus Icutnyosaurus, Konig.—Humerus articulating distally with only the radius and ulna, which are short and in close apposition. A. Latipinnate Group.—Pectoral limb with the third digit (that arising from the intermedium) containing two longitudinal rows of bones and two centralia; radius very short, with entire anterior border. a. Campylodont subgroup.— Roots of the teeth enveloped in cement ; humerus with prominent trochanteric ridge. a. Femur very short, with trochanteric ridge enormously developed. 5. IcHTHyOsAURUS CAMPYLODON, Carter. Up. Cretaceous, Europe. *6. i INDICcUS, nobis. Up. Cretaceous, 8. India. eile A Srrompucki, Meyer. Neocomian, N. Germany. *8, Bs POLYPTYCHODON, Koken. Neocomian, North Germany. LR. Lydekker—Note on the Ichthyopterygia. dll 8. Femur longer, with trochanteric ridge less developed. *9. IonrHyosauRus (?) ovatts, Phillips. Kimeridge Clay, Eng. 10) ss (2?) TrHyrEosPponDYLUs, Phillips. KimeridgeClay, England. Syn. (?) I. brachyspondylus, Owen. (?) I. thyreospondylus, Owen. 11. IchTHYosauRUS LEPTosponDYLUS, Wagner. Kimeridgian, : Bavaria. 12. IcurHyosaurus ENTHECIODON, Hulke. Kimeridge Clay, England. 15. IchrHyosauRuS TRIGONUS, Owen. Kimeridge and Oxford Clays, England. Syn. (?) I. posthumus, Wagner. Kimeridgian, Bavaria. *14, IcurHyosaurus (?) pizatatTus, Phillips. Kimeridge and Oxford Clays, England. *15. IcHTHYOSAURUS HILDESIENSIS, Koken. Neocomian, North Germany. b. Typical subgrowp.—Roots of the teeth without cement ; humerus without prominent trochanteric ridge. 16. IcnrHyosaurus communis, Conybeare. Low. Lias, England. te Fa BREVICEPS, Owen. is re 18. 3 ConyYBEARI, n.sp., nobis. __,, 19. x INTERMEDIUS, Conybeare. _,, a B.—Longipinnate Group.—Pectoral limb with the third digit con- taining one longitudinal row of bones and a single centrale; radius nearly square, and usually with notched anterior border. a. Acutirostrine subgroup.—Teeth small and cylindrical, coracoid without posterior notch ; head of humerus oblong. 20. IcHTHYOsAURUS INTEGER, Bronn. Up. Lias, Wiirtemberg and (?) England. 21. IcHrHyosAURUS AcUTIROSTRIS, Owen. Up. Lias, Europe. Syn. I. longipennis, Mantell. I. microdon, Wagner. I. quadriscissus, Quenstedt. I. Zetlandicus, Seeley. I. longifrons, Owen. b.—Tenuirostrine subgroup.—Teeth small and cylindrical ; coracoid with posterior notch; head of humerus triangular. 22. IcHTHYOSAURUS TENUIROSTRIS, Conybeare. Lias, Europe. Syn. I. grandipes, Sharpe. 23. IcnTHyosAuRUS LATIFRONS, Konig. Lias, England. Syn. I. longirostris, Owen. (?) I. longirostris, Jager. c. Platyodont subgroup.—Teeth large, either cylindrical or cari- nated ; coracoid without posterior notch; head of humerus triangular. 24. IcnTHYOSAURUS LoNCHIODON, Owen. Low. Lias, England. Zon 3, s PLATYODON, Conybeare. Low. Lias, England. Syn. Ichthyosaurus giganteus, Leach. ol2 R. Lydekker—WNote on the Tehthyopterygia. 26. IcuTHYOSAURUS TRIGONODON, Theodori. Up. Lias, Bavaria. TI]. Genus Mrxosaurus, Baur. Humerus articulating with the radius and ulna, which are elongated and separated by an interval. 27. Mixosaurus cornattanus (Basani). Up. Lias, Italy. Syn. Ichthyosaurus cornalianus, Basani. The forms indicated by the under-mentioned names cannot be classified, and it is probable that several of them are synonyms of those already mentioned. 28. Ichthyosaurus equalis, Phillips. Kimeridge Clay, England. ZO rae » angustidens, Seeley. Up. Chalk, England. Oe rhese a (?) atavus, Quenstedt. Mid Trias, Germany. 5) oA », australis, Hector. (?) Trias, New Zealand. (?) = Mixosaurus. SB sys ,, calorodirus, Seeley. Kimeridge Clay, England. SOwe hiss » (2) carinatus, Sauvage. Up. Trias, France. ? = Mizxosaurus. S47 4) » coniformis, Harlan. ? Lias. SOM » erassicostatus, Theodori. Up. Lias, Bavaria. SOMME. », gaudensis, Hulke. Reputed Miocene, Malta. Sais », hexagonus, Theodori. Up. Lias, Bavaria. » hygrodirus, Seeley. Kimeridge Clay, England. SOA he » imgens, Theodori. Up. Lias, Bavaria. AlN fae 5 macrophthalmus, Theodori. Up. Lias, Bavaria. 7) ah aN » megalodirus, Seeley. Oxford Clay, England. AD 93 » Nordenskisldi, Hulke. Trias (?), Spitzbergen. Ar il iiss » planartus, Theodori. Up. Lias, Bavaria. 44. ,, » polaris, Hulke. ‘Trias (?), Spitzbergen. 45. ,, » (2) rheticus, Sauvage. Up. Trias, France. (?) = Mixosaurus. AG Lat 35 » triscissus, Quenstedt. Up. Lias, Wiirtemberg. The name I. latimanus, as will be noticed below, must be discarded. The names I. Bonneyi, I. Doughtyi, and I. platymerus, Seeley, and I. advenus, Phillips, are merely MS. ones; the first three being applied to specimens from the Cambridge Greensand, and the fourih to vertebrae from the Stonesfield slate. J. Walkeri, Seeley, hag been made the type of Cetarthrosaurus. In regard to the two new species above mentioned Onhihalmon ag, us cantabri igiensis is founded on a small humerus from the Cambridge Greensand in the British Museum (No. 43989), which differs from that of O. icenicus in having the three distal facets of nearly equal dimensions. The name Ichthyosaurus Conybeari is applied to an imperfect skeleton of a small Ichthyosaur in the same collection (No. 38523) from the Lower Lias of Lyme-Regis, which differs from I. communis in the notching of the anterior border of some of the phalangeals of the pectoral limb, and in the relatively longer skull ; while it is distinguished from I. intermedius by the greater width of the pelvic limb.. It is possible that I. latimanus, Owen, may be R. Lydekker—Note on the Ichythopterygia. d13 identical with this form, but since, as I shall show on a subsequent oceasion, that species appears to have been founded by mixing up the characters of two specimens, which are apparently specifically distinct, the name must be abolished. It is not improbable that one or more of the Kimeridgian species mentioned in the Campylodont subgroup may be referable to Ophthal- mosaurus, and I think there is considerable probability of this being the case with Ichthyosaurus (?) ovalis, in which the contour of the vertebre differs considerably from that obtaining in Kimeridgian species undoubtedly belonging to Ichthyosaurus. It may therefore prove that Ophthalmosaurus icenicus is even specifically identical with this form. In respect of other species, I have great doubt whether I. enthectodon is distinct from the continental I. leptospondylus of the same geological horizon, but since I cannot certainly say that the two are identical, it is preferable to allow both names to stand for the present. I find by a comparison of the type skulls of the so-called I. Zetlandicus! of the Upper Lias of Whitby, and J. longifrons of that of Normandy, that these two are evidently closely allied forms ; and since certain differences in the arrangement of the bones of the quadratic region do not appear to me to be, at the most, of more than racial importance, I am inclined to refer both forms to a single species. A comparison of the pectoral limb of the Normandy torm with that of the Whitby I. acutirostris shows, moreover, that both are of the same structural type ; and since other Upper Liassic skulls from Whitby, which are indistinguishable from the type of I. Zetland- icus, agree equally closely with that of the former, I am disposed to unite both I. Zetlandicus and I. longifrons with I. acutirostris. I find, moreover, that skeletons from the Upper Lias of Wiirtemberg in the Museum, which agree with the one figured by Renevier in the “ Bull. Soc. Vaudois ” for 1885 as I. quadriscissus, Quenstedt, and also with those from the same region figured by Prof. Seeley in the ‘ British Association Report ” for 1880, without specific determination, present all the characters of the present species. And J am confirmed in this conclusion by finding it stated by Theodori in his Monograph of I. trigonodon that I. acutirostris is the most common form found in the Upper Lias of Bavaria and Wiirtemberg. The sketch of a skull from the Upper Lias of Banz, in Bavaria, made by Theodori _and presented by him to Sir R. Owen, which is preserved in the British Museum, also affords important evidence in this direction, since it shows that the premaxilla and lachrymal did not unite below the nares to exclude the maxilla from that aperture ;—a feature which is characteristic of the skulls described as I. Zetlandicus and I. longifrons. I may observe also that, as Mr. W. Davies first pointed out to me, I. longirostris, Owen, appears to be identical with I. latifrons, Konig. The former name was, however, originally applied by Jager 1 T am glad to take this opportunity of thanking Prof. T. McKenny Hughes, of Cambridge, for his courtesy in permitting the type skull of I. Zetlandicus to be sent to the British Museum for comparison. ol4 G. A. J. Cole—Apparatus for Flame-Reactions. to specimens from the Upper Lias of Wiirtemberg which are pro- bably also specifically the same. In conclusion it will be interesting to draw attention to a pectoral limb of I. acutirostris (quadriscissus), figured by Dr. O. Fraas in the Jahresh. Ver. Nat. Wiirtt., 1888, pl. vii., in which the contour of the integument is perceived. It appears from this figure that the integuments were produced a considerable distance on the posterior border of the paddle so as to form a large fold in the axillary region. VIJ.—On Simpxe Apparatus ror Uses IN THE OBSERVATION OF Fiamer-REACTIONS. By Grenvitte A. J. Coun, F.G.S. G EOLOGISTS, who are again and again forced to deal with the 1 most minute or fragmentary specimens, and who find it impos- sible to cultivate, during their surveys of the earth, the methods perfected by the mineralogist in his learned leisure, have fully recognized the importance of Prof. Szabo’s tabulation of the flame- reactions of the felspars. Since the accuracy of the results obtain- able depends largely upon the position of the mineral-particle in the flame, I venture to call attention to a form of support that has proved in practice as convenient, and efficient as it is simple. Following a long way in the wake of Prof. Miller’s ingenious goniometer, the materials of this little instrument are essentially wire and cork. A small gallipot, such as is used for Liebig’s extract, forms a base that is clean, strong, and adequately heavy. A brass wire, about 5 mm. in diameter, passes through the cork of this, and rises 15 centimetres above it, carrying a stout cork A, which can be slid up and down to any level. A steel wire or knitting-needle, some 25 cm. long, is pushed horizontally through A, the last 7 cm. on either side being then bent forward at right angles. Two small corks, B and B’, are carried by the parallel arms thus formed, and support, by means of a knife-slit in the top of each, the fine platinum wires employed. B can be slipped off the steel wire, the mineral fragment can be attached, with Prof. Szab6’s precautions, to the platinum loop, and the carrier replaced without fear of loss by jarring. B’ can be used for a type-specimen to be com- pared with that under examination, the wires on both corks being J. W. Davis—Note on Scymnus, N. Zealand. 315 adjusted to exactly the same level, and one or other being brought at will into the flame. The cork A being set approximately at the proper height, the rotation of the steel wire within it moves B and B’ equally in vertical planes, and gives a delicate means of fine adjustment. To secure uniformity of position in successive experiments, the platinum loop carrying the specimen is brought, in the first trial, to the exact level of the top of the bunsen burner, or, in the second and third trials, to the level of the top of the iron cone. A small plate of wood, C, of the thickness of 5 mm., is then slid under the gallipot, the specimen being thus raised to the position adopted by Prof. Szabo, without any of the difficulties that so often arise from the jarring or stiffness of motion in more elaborate supports. The dimensions above given are those adapted to a bunsen burner of ordinary height and ordinary diameter of base. For packing, the erection can be taken down, and the 5-millimetre plate and the smaller corks can be kept inside the gallipot till required. This obvious and simple contrivance, with its smoothness and uniformity of adjustment, may possibly facilitate to some busy geologist the practice of the method of flame-reactions; and a sense of the value, not to say the charm, of the observations of Prof. Szabo must be my excuse for thus describing it at length. VIII.—Nore on a Spectes or Scyuvus FROM THE UPPER TERTIARY Formation oF New ZEALAND. By James W. Davis, F.G.S. ik a Memoir recently published “On the Fossil Fish Remains of the Tertiary and Cretaceo-Tertiary Formations of New Zea- land” (Transactions of the Royal Dublin Society, vol. iv. ser. 11. p. 11, pl. vi. fig. 22) there is described a small tooth as an immature example of Carcharodon angustidens, Ag. The specimen was in- cluded amongst a large number of others forwarded for examination by Sir James Hector, Director-General of the Geological Survey of New Zealand; it is a small tooth, exquisitely preserved, and does not exhibit any, signs of abrasion by use, which led to its being provisionally considered as the tooth of a young shark, and its form and minutely serrated margin appeared to indicate that its relation- ship was with Carcharodon. JI am indebted to Mr. A. Smith Wood- ward for the suggestion that the tooth belongs to one of the Spinacide ; a re-examination has convinced me of the correctness of this sugges- tion, and that it is an example of the genus Scymnus, to which genus I have no hesitation in transferring it. The occurrence of this specimen in the Napier series of the Hsk River is interesting from the fact that the only existing species, Scymnus lichia, is found inhabiting the Mediterranean Sea, and that part of the Atlantic immediately adjoining. The genus is represented in the Miocene Molasse of Baltringen by Scymnus triangulus, Probst, a small thin tooth, with a triangular crown anda more or less rectangular base divided into two parts by a vertical slit ; from the Pliocene of Tuscany 316 Notices of Memoirs—A. Smith Woodward—On Selachians. and the Bruxellian of Woluwe St. Lambert. The New Zealand species may be distinguished from this one by its larger size, more acuml- nate apex, and by aslight lateral projection from the base of the crown. The Napier series, from which it was obtained, occupies a much higher horizon than the Baltringen Molasse; by the Survey they are considered to be the Upper beds of the Pliocene, whilst Professor Hutton tabulates them as Pleistocene. They underlie the dispersed gravels and peat mosses, the latter containing the bones of the recently extinct Moa. Though the existence of Scymnus is unknown in the southern seas, its fossil remains in these beds indicate that its extinction has happened during comparatively recent times. It is desirable that the species should be distinguished, and I suggest as the nomen triviale, Scymnus acutus. REFERENCES TO SPECIES PREVIOUSLY DESCRIBED. Scymnus triangularis. J. Probst. Wiirth. Jahresb. v. xxxv. p. 174, pl. iii. figs. 35, 86 (1879). Molasse, Baltringen, Wurtemberg. S. majort. R. Lawley. Nuovi Studi sopra ai Pesci, etc., p. 38, pl. i. fig. 17 (1876). Pliocene, Tuscany. S. trituratus. J. Probst. Wirth. Jahresb. v. xxxv. p. 176 (1879). F. Noetling. Sitzb. Ges. Naturf. Freunde Berlin, 1886, p. 17 =Corax tritu- ratus. T. C. Winkler. Archiv. Mus. Teyler, v. iv. fase. i. p. 27, pl. ii. fig. 13 (1874). Bruxellian, Woluwe St. Lambert, near Brussels. CHEVINEDGE, Hauirax. IN @ ce Gre SS @ 7b Vie @ aes S- NG I.—PatmonroLogicaL Contrisutions to SenacHtAN Morpuotoey.! By A. Surra Woopwarp, F.Z.S., F.G.S. Y\HE author discussed two features in Selachian anatomy presented by fossils from the Chalk of Mount Lebanon. An examination of the so-called Scyllium Sahel-Alme, which is certainly a member of the Scylliide, shows that the lateral line of this fish was supported by a series of half-rings, exactly like those met with in Squaloraja and the Chimzroids—a character apparently hitherto unrecognized among undoubted Selachii. The eanal of the lateral line in the Cretaceous fossil was thus presumably an open groove; and only two living Sharks, Echinorhinus and Chlamydoselachus, both com- paratively primitive, have yet been described as exhibiting such a condition. ‘The second discussion related to the pelvic cartilage of Cyclobatis, one of the Trygonide. It had long been recognized that the pair of anterior processes were the homologues of the so-called “prepubics,” and the author now attempted to show that the large bent, lateral processes were dorsally placed, and might thus be regarded as “iliac.” It seems not improbable that the reflexed distal extremities of the latter originally supported the metapterygia of the pectoral fins, in the same manner as the propterygia were con- nected with the antorbital (post-palatine) cartilages. 1 Proceedings of Zoological Society of London, Feb. 21, 1888. Notices of Memoir—J. A. Brown—Mammoth at Southall. 317 I1.—Unterprvoniscue Crinoipen. Von Dr. Ortro Fonimann. Verh. d. nat. Ver. Jahrg. xxxiv. 5 Folge, 1V. Bd. pp. 113-188, HIS paper gives detailed descriptions of a numerous suite of Crinoids collected by Herr B. Stiirtz from the Lower Devonian strata of Bundenbach and Gemiinden. ‘These fossils are mostly in a pyritized condition, but they have been treated by the same methods which proved so successful with the Asteroidea from the same beds, and many new structural features have been brought to light. The following new species are described and figured :— Triacrinus elongatus, Calycanthocrinus (n. g.) decadactylus, Taxocrinus Stuertzii, T. Grebet, Codiacrinus Schultzei, Ctenocrinus acicularis, C. stellifer, and C. rhenanus. Additional details are likewise given of twelve other species previously described from the same geological horizon. IIJ.—Discovery or HirpHas PRIMIGENIUS ASSOCIATED WITH FLINT Imptements at Sournatt. By J. Auten Brown, F.G.S., Geologists’ Association, 6th May. URING last year some important drainage works were carried out at Southall, and sections were exposed in Windmill Lane, a road running from Greenford, through part of Hanwell, across the Great Western Railway to Woodlake, skirting Osterley Park, as well as in Norwood Lane, leading from Windmill Lane, south- westward. The remains of the Mammoth were discovered in Norwood Lane, about 550 yards from its junction with Windmill Lane, and at the 88 foot contour. They were embedded in sandy loam, underlying evenly stratified sandy gravel, with a thin deposit of brick-earth about a foot in thickness, surmounting the gravel—in all about } feet of river drift above the fossils. The labourers described the tusks as being found curving across the “shore” or excavation, attached to the skull, parts of which, with the leg-bones, ete, and teeth were exhumed. Other bones were exposed in the side of the cutting. It is probable that the whole of the remains might have been obtained if they could have been carefully exhumed, and if means had been at hand to remove them, as they were in a soft pulpy condition. The author obtained many of the bones in a fragmentary state, including parts of the fore limbs and jaw, and portions of the tusks, as well as two of the teeth, which were much better preserved; a third molar was found, but broken to pieces by the labourers. Although many of the bones were when gelatinized too much broken to admit of determination with certainty, they were quite unrolled and the joints and articulations of the leg bones and the teeth were unabraded. There can hardly be a doubt that the bones of the whole of the fore part of the Elephant, if not of the entire skeleton, were in juxtaposition. Several flint implements were found in Norwood Lane in close 318 Notice of Memoir—J. A. Brown—Mammoth at Southall. proximity to the remains, and a well-formed spear-head nearly five inches in length, of exactly the same shape as the spear-heads of obsidian until recently in use among the natives of the Admiralty Islands and other savages, was discovered in actual contact with the bones. Smaller spear-head flakes less symmetrically worked were also found at this spot. They are formed for easy insertion into the shafts by thinning out the butt end, similar to those found abundantly by the author at the workshop floor, Acton, and described by him in his lately published work, ‘ Paleolithic Man in N.W. Middlesex.” Among the implements found here is an unusually fine specimen of the St. Acheul or pointed type, 8 inches long, of rich ochreous colour and unabraded, and a well-formed lustrous thick oval imple- ment pointed at one extremity, rounded at the other, and also unrolled. From the adjacent excavations in the Windmill Road several good specimens of Paleolithic work were also obtained, including two dagger implements with heavy unworked butts and incurved sides converging to a long point; these were evidently intended to be used in the hand without hafting. Also a form of instrument character- istic of the older river drift, convex on one side and slightly concave on the other near the point and partly worked at the butt; with these were two rude choppers or axes, two points of implements with old surfaces of fracture, and several flakes. It is remarkable that almost all the principal types of flint implements found in the oldest drift deposits are represented in the collection found in the vicinity of the remains of the Elephant. Mr. J. Allen Brown accounts for the deposit of the remains of the Mammoth and associated human relics at this locality by the fact that the underlying Hocene bed rises to within two or three feet of the surface a few yards west of the spot where the bones and imple- ments were found, while towards the Uxbridge Road and upper part of Windmill Lane, the drift deposits thicken, until at no great distance they have a thickness of 14 to 17 feet. Thus the river- drift rapidly thins out and the upward slope of the London Clay reaches nearly to the surface at about the 90th foot contour, and as the level at which the fossils were found (18 feet from the surface) would represent the extent of the erosion and infilling of the valley which had then taken place, it is probable that the higher ground formed by the up-slope of the London Clay then formed the banks of the ancient river, or if another thick bed of drift should be found still further west, in a depression of the Tertiary bed, such as often occurs. The intervening higher ground would form a small island in the stream, in either case a habitual land surface would be formed, with shallow tranquil waters near the banks, not impinged upon by the currents which subsequently set in this direction as shown by the deposit of coarse stratified gravel above the loamy bed and remains. The author is thus led to the conclusion that the carcase of the Elephant either drifted into the shallow water near the bank, or else, which seems more probable from the presence of so many Reviews—Lapworth and Page’s Geology. 319 weapons near the spot, including the spear-head, found with the remains, that the animal was pursued into the shallow water by the Paleolithic hunters and there became “ bogged.” Whatever hypo- thesis may be accepted, there is no evidence of any greater flood or inundation than would often occur under the severe climatic conditions which prevailed during the long period which intervened between the formation of the higher benches of river drift and that of the mid-terrace, only 25 to 80 feet above the present river, in which the remains of the Mammoth and the extinct Quaternary mammalia are more frequently met with under similar conditions. Nor does there appear to be any more reason for ascribing the extinction of the great Quaternary pachyderms to a sudden cata- strophe or cataclysm than there is for the extinction of some other Pleistocene forms, such as the Great Irish Deer ; while the difficulty involved in this hypothesis is still further increased by the fact that other animals, such as the Reindeer and Musk-sheep of northern habit, as well as southern forms like the Hippopotamus, were not utterly destroyed with their contemporaries by the same cause, but merely migrated to regions more suited to them, as the climatic and other conditions of this country changed. ase) dal} WA ae Jer Wwe 4 J.—Inrropuctory Text Book or Gronocy. By Davin Pagz, LL.D., F.G.S. Revised and in great part rewritten by CHaRLEs Larworrn, LL.D., F.G.S. Twelfth and enlarged edition. 8vo. pp- 809. (London and Edinburgh, Biackwood & Sons, 1888.) HE publishers of this work are fortunate in having secured Prof. Lapworth’s services in bringing out a new edition of it. While careful to retain the arrangement of the original, and whatever was valuable of its matter, the editor has been bold enough to sweep away all that is cumbrous or obsolete, and sufficiently painstaking to rewrite whole chapters in order to bring them abreast of modern geological thought. The result is that he has produced a book which from its simplicity and clearness will be useful for schools, while the introduction of specific names, the careful attention paid to the derivation and meaning of terms, the alternative tables and fresh points of view brought into the “ Recapitulations,” the real glimpse (not a mere catalogue) of foreign strata, and the new classification of animals and plants, will restore it to its place as an examination text- book. But beyond and above this, the sections on Petrological geology, on the older Paleozoic or Proterozoic rocks, and last but far from least, those on the Igneous and Metamorphic rocks, are well worthy the attention of specialists in these lines of research. That the improvements are wide-spread as well as concentrated we see from the fact that this edition contains more than 70 additional pages and 50 new illustrations. Many of the old artificial-lookine sections are replaced by real ones (like the effective drawing of rock strikes in p. 62 and the map and sections on p. 63) and some of the 320 Reviews—Lapworth and Page’s Geology. old fossils are removed and their places taken by others of more value in the present state of science. Professor Nicholson has lent some of the beautiful drawings from his Paleontology, such as Mosasaurus, Dicynodon, Hesperornis, and Odontopteryx (whose arti- ficial teeth, as a lady student once called them, are well shown), and some of the older pictures like the rather blasé Pterygotus of p. 186 look poor beside these modern rivals. Jn the short sketch of the objects and scope of geology enough elementary knowledge is imparted to enable the student to follow the succeeding chapter on dynamical agencies modifying the earth’s crust; but a great deal of space is saved in this section to be used later on more purely geological matters, the author rightly thinking that much of this will have been taught as Physiography ; we may illustrate the thoroughness and conciseness of this part by a single sentence on the formation and maintenance of waterfalls. ‘‘ Where a hard stratum rests upon one of a softer nature, erosion is arrested above and behind, while it goes on unchecked in front and below.” The Petrological division is almost too brief, but we notice some good illustrations and oblique and inosculating (loop) faults are defined. The Historical Geology of the work is not only thorough, but exceedingly interesting, for the author has the faculty of grasping the general facies of a system and presenting it to his readers as a whole, so that he not only gives type sections and descriptions of the fauna and flora, but in a few graphic touches notes their varia- tions in our own limited area and over the rest of the world. In . order to this he does not fetter himself by any single literal plan, but moulds his plan to his subject (this is seen in other chapters), and so presents some systems differently from others. ‘The Archean chapter is an interesting one, and the author’s views may be gleaned from this passage :—‘ As most of the foliated Archean rocks occur in areas of regional metamorphism, it may be regarded as tolerably certain that they owe their schistose characters to the same agency, and that we are not dealing in a series of such foliated rocks with rock systems, but with petrological complexes.” There is a curious passage on page 150, and one can imagine that the author felt a little tempted to add to his list the Dimetian, Arvonian, Lewisian, and Monian systems with their synonymous localities. It is, of course, needless to say that the hand of the master is clearly traceable through the Cambrian, Silurian, and Ordovician sections, and in the latter he has again raised the Shropshire standard for comparison. The pale- ontology of each system is gone into in detail, repeated stress being laid on the introduction, modification, and extinction of species ; its volcanic energy is described, and space is generally found for an account of the economics and scenery of the rocks and of the phases of Physical Geography to which each is due. Liberal space is allotted to the Carboniferous system, which is used as an illustration of the method of working out a system of rocks in its entirety. But we have not time to deal with each system in detail ; the advantages of the method of treatment, the amount of matter introduced, its Reviews—Lapworth and Page’s Geology. 321 reliability, and the attractive manner of its setting forth, will be best appreciated by the readers and students for whom the book is meant. We have purposely delayed to speak of the chapters on Igneous and Metamorphic rocks, as these chapters will be the ones to attract most attention. Both are treated from the point of view of the structural geologist, but one who is well acquainted with the minuter and microscopic characters of the rocks he speaks of. The classification of Igneous rocks adopted has a chemical and mineralo- gical basis, the minuter subdivisions being effected by differences in origin and texture. A notable passage suggests, “It is far more probable, however, that they (granitic bosses) are really laccolites or intrusive sheets upon a gigantic scale, the plane of intrusion and separation, instead of being confined toa single bedding-plane, cross- ing the bedding of the rocks of the district more or less irregularly and obliquely.” Fig. 55. Fie. 56. Figures illustrating the structures of the Schistose Rocks. Figs. 53, 54. Macro-structures. Fig. 53. Flaser gneiss (Flaser structure), natural size. Fig. 54. Augen-granulite (Augen structure), natural size. Figs. 55, 56. Micro-structures. Fig. 55. Mylonite (Mylonitie structure), highly magnified, Fig. 56. Mica schist (Granulitie structure), highly magnified. The metamorphic chapter derives great interest from the Survey paper read at the Geological Society a month ago, in which all Prof. Lapworth’s conclusions in the Highlands were confirmed. The terms DECADE III.—vVOL. V.—NO. VU. 21 322 Reviews—Lapworth and Page's Geology. Hydro-, Pyro-, and Dynamo-Metamorphism are used ; the first stages of their action producing altered, but the higher stages metamorphic rocks. Schists are defined as Foliated: crystalline sas, 3 in which the “ folia are not in parallel sheets but thin lenticular plates, each plate thickening in the middle,” ete. We have next descriptions of Augen structure, flaser structure (formed of lenticles or ellipsoidal patches or phacoids in a fine base), granulitic and mylonitic structures, the latter being defined as “Compact slaty-looking rocks, composed of material ground to powder, or rock flour, between the great moving masses in the over-faults of that region, like corn between a pair of millstones.” The author takes the responsibility of such of these terms as are due to him, and whatever may be the fate of the terms, the origin of the structures as made out in the Highlands seems to be almost undisputed. By Messrs. Blackwood’s kindness we are enabled to reproduce the figures which accompany these descriptions. Then follows an account of the two main sets of opinions on the origin of these rocks, leading to a description of the Highland section. The picture of this is almost an exact copy of Murchison’s, teaching us that to the mere drawing of sections must now be added the skilled interpretation of them. We then have a highly condensed, but very valuable account of the Deformation Theory of Metamorphism which we print in full :— “Founded upon the conclusions drawn from all these discoveries, a new theory of the cause of the association and of the varied petro- logical characters of the rocks ina district of regional metamorphism is being gradually developed at the present time—a theory most closely related to the original suggestions of Darwin, Scrope, and Sharpe. According to these new views, the rocks in such a district do not necessarily belong to any one distinctive geological period, but may be of various geological ages, owing their present association to the effects of lateral pressure, which has more or less obscured the evidences of their original relationships. Some metamorphic areas may possibly be wholly Archean ; others may be composed of patches originally either Archean, post-Archean, plutonic, sedimentary, or volcanic. The present structures of the rocks in various parts of such an area may be either original or secondary, according to the mode or degree of the local metamorphism to which they have been subjected. The granites, gabbros, etc., in such a region are unaltered plutonic rocks; the quartzites, crystalline limestones, and the like, are probably sediments only partly altered. The gneissoid rocks may be either Archean or post-Archzean plutonic rocks, or felspathic sediments foliated by pressure, intrusion, veining, and the like. The schists may be either metamorphosed sediments, retaining locally their original bedding (where altered by pyrometamorphism and the like), in dynamo- metamor phic rocks showing only secondary struc- tures, but which may have been originally either eneissic, plutonic, or sedimentary rocks, but whose ingredients have ‘een more or less completely rearranged both structurally and mineralogically. In fine, a metamorphic. area is a petrological complex whose altered rocks have a common foliation. The strike of foliation in such a district is Reviews—Lapworth and Page’s Geology. 320 related to the general strike of the sheets of sedimentary or crystalline rocks which formed its main masses at the time of its final folding and shearing; the dip of foliation is simply the local direction of shear,—i.e. is related to the direction in which the mass to which it belonged was giving way. Like cleavage, it may locally coincide with the original bedding ; but it normally crosses the bedding at an angle, and traverses aqueous and igneous rocks alike. The planes of schistosity are those planes along which the rocks yielded to the lateral pressure or torsion, and these yielding planes may be of all grades of importance, from the great overfaults, along which solid masses of enormous extent were thrust forward, in some cases for scores of miles, down to the minutest planes separating the micro- scopic folia of the slaty schists. These planes cut the rock up into lenticular patches or ‘phacoids,’ which, like the yielding planes themselves, are of all gradations of size—from the mountain masses riding out along the great overfolds and overfaults, down to the ‘eyes’ of the ‘augen’ schists. The mechanical effects wrought by the shearing and deformation of the phacoids show of necessity a corresponding gradation, the conditions at one extreme giving rise to coarse rock-breccias ; in medium cases to flaser structures and foliation ; at the other extreme to the compact, stringy mylonite, in which the original material has been torn and ground to rock-dust. Parallel with these mechanical changes, but not necessarily accompanying them, we note a series of chemical changes of rising grades of impor- tance—a larger and larger portion of the rock undergoing deforma- tion becoming recrystallized, until finally, it may all become trans- formed into foliated crystalline rock. The maximum of mechanical effects seem to have been wrought where the rock yielded to the excessive pressure and torsion mainly along certain definite planes (shear planes or gliding planes) or areas within the mass; the maai- mum chemical effects where the deforming stresses affected all the particles of the mass alike, the rock yielding or flowing in the manner of a plastic or liquid body. In some minor areas the results effected by dynamo-metamorphism possibly approximate to those wrought by pyro-metamorphism, and we may have what has been called stratifi- cation foliation. In general, however, the foliated rocks have been sheared, and the primary structures have all been more or less obliterated. But, as a metamorphic region may be subjected to suc- cessive earth-movements acting at different times, and from different directions, we occasionally find a newer and more or less incomplete foliation crossing an older foliation, or the rocks may show traces of a foliation ofa still earlier date: the successive foliation planes being in different stages of development, preservation, or obliteration.” So much has been done in so little space that it seems greedy to ask for more; still, in the next edition we hope the author may be able to supplant the rest of the old work which he has left ; to give us a few more figures of type sections, a little more space to the dates and function of earth-movements, and even perhaps also to the physical geography of the different periods. It seems unnecessary to put into words what it is quite certain all readers will think of 324 Revriews—Fossil Fauna of Sweden. this book; but among the expressions of opinion one will be fre- quent, that it has those qualities which we always recognize in a man of power—strength and firmness combined with a rare modesty. Il.—List or tHe Fosstz Faunas or Swepren. Edited by the Paleontological Department of the Swedish State Museum (Natural History). J. Camprian anp Lower Sinurian. 8vo. 24 pp. III. Mesozorc. 20 pp. (Stockholm, 1888, Printed for the Museum by P. A. Norstedt & Sodner.) HE Authorities of the Swedish State Museum intend to publish a list of the fossils (excepting the plants) occurring in the various geological formations of Sweden, and two parts have just been issued. The first of these has been prepared by Prof. G. Lindstrom, and contains the names of species from the different sub- divisions of the Cambrian and Lower Silurian (= Ordovician) in that country. The Cambrian is divided into the following zones, the fossils in each being separately enumerated :—1, Oldest Sand- stone Beds, the Eophyton and Fucoid Sandstones; 2, Paradowides Beds, including therein the zones of, (a) Olenellus Kjerulfi; (b) Paradoxides CElandicus; (c) P. Tessini; (d) P. Davidis; (e) P. Forchhammert; (f) Agnostus levigatus; 8, Olenus Schists, and 4, Dictyonema Slate. The Lower Silurian comprises, 1, Ceratopyge Limestone; 2, Lower Graptolite Schists; 38, Orthoceratite Lime- stone; 4, Middle Graptolite Schists; 5, Chasmops Limestone; 6, Trinucleus, Schists; 7, Brachiopod Schists; 8, Upper Graptolite Schists; and 9, Leptena Limestone. From the Cambrian strata 141 species are enumerated, and 627 from the Lower Silurian, thus making a total of 768 species. Of these no fewer than 3865, or nearly one-half, are Trilobites, next in abundance are Graptolites with 146 species, followed by the Brachiopoda with 89 species, and the Cephalopoda with 50 species. Prof. Lindstrom remarks that not a single species is recorded as common to the Cambrian and Lower Silurian formations in Sweden, but the latter contains 19 species which recur in the Upper Silurian. Part II., containing a List of the Upper Silurian Fauna, will be issued in the Autumn; Part IIJ., which has been prepared by Prof. Bernhard Lundgren, records the Mesozoic Fauna. Of the lower portions of the Mesozoic series only the Rheetic and Liassic strata are developed in Sweden, and in these there’seems to be but a scanty fauna, for not more than 24 species are enumerated from the former, and 129 from the latter group. ‘There is then a wide gap in the middle portion of the Mesozoic series, until reaching the higher members of the Cretaceous strata, which are richly fossili- ferous, the list containing 456 species, mainly from the zones of Actinocamax mammillatus and of Belemnitella mucronata. The value of these Lists, prepared as they have been by such well-qualified authorities, will be recognized by all paleontologists, and we hope that the other parts will be successfully completed. Reviews—Dr. Geo. Baur—Ichthyopterygia. 329 T]I.—On rue MorpHonocy AnD ORIGIN oF THE ICHTHYOPTERYGIA.' By Dr. Grore Baur, Yale College Museum. HE present paper is one of the results of Dr. Baur’s recent tour in Europe, during which he was enabled to examine the Fossil Vertebrata in most of the principal Museums of the Continent and England. The various known characters of the Ichthyopterygian skeleton are reviewed and compared especially with the existing Sphenodon; and the conclusion is arrived at, that these Mesozoic marine reptiles bear the same relation to certain ancestral terrestrial Rhynchocephalia, that is apparently borne by the living Cetacea to early ungulate Mammalia. The skull is only comparable with that of the Rhynchocephalia (especially Sphenodon) and the Lacertilia. The only real difference is that, as in the Cetacea, the facial portion has been very much elongated. ‘The general structure of the skull resembles that of the Dolphins: in its morphology, it is a copy of the Sphenodon skull.” Most of the accepted interpretations of the cranial bones are adopted, but a correction is offered in regard to the large bone forming the postero-external boundary of the supra- temporal fossa. This is determined to be the supratemporal element of the Lacertilia, and in Sphenodon is said to be united with the squamosal; the bone in Ichthyosaurus has been termed mastoid by Owen, and squamosal by Seeley and Cope. Between this element, the postfrontal, postorbital, quadratojugal, and quadrate, is articu- lated the true squamosal, named prosquamosal by Owen, and supra- quadrate by Seeley. After the detailed comparisons, Dr. Baur proceeds to discuss the morphology of the Ichthyosaurian paddle. The most primitive example known is that of Ichthyosaurus cornalianus, Bassani, from the Trias of Besano, Italy, which is placed in a new genus, Mixosaurus. The radius and ulna are elongated bones, with a considerable intervening space. The paddle of Baptanodon or Sauranodon is regarded as the most specialized form, and the bone termed by Marsh “intermedium ” is interpreted as ulna, while the so-called “ulna” is held as probably representing the pisiforme. The oldest Ichthyopterygia had few phalanges and not more than five digits; later, through the adaptation to the water, the number of phalanges increased, ‘and more digits appeared, chiefly by division of the former, but sometimes by new formation on the ulna side. An interesting analogous case is noted in the manus of a Manatee, in which Dr. Gadow has observed an exceptional increase of the phalanges beyond the normal Mammalian to the number of three. In conclusion, Dr. Baur proposes the following classification of the Ichthyopterygia :— Group A. Radius and ulna elongated, separated by a space in the middle. Teeth of two forms, but not so numerous as in the Ichthyosauride. Small animals. Triassic. Family, Mixosauride, Baur. Genus, Mixosaurus, Baur. Group B. Radius and ulna short bones, touching each other. Teeth well developed and numerous. 1 American Naturalist, 1887, pp. 837-840. 326 Reviews— Lobley’s Geology for All. Family, Ichthyosauride, Bonaparte. Genus, Ichthyosaurus, Koenig. Also undefined genera. Group C. Radius, ulna, and a third bone articulating with the humerus. Teeth rudimentary or absent. Family, Baptanodontide, Marsh. Genus, Baptanodon, Marsh. A. S. W. TV.—‘“Gxotocy ror Att.” By J. Logan Lostry, F.G.8. (London, Roper & Drowley, 1888.) 6¢ ( X EOLOGY FOR ALL” is a very attractive title, and we wish that such a work may succeed, for no little credit would attach to the man who could enable the general public to master the alphabet of geology. Outside a limited circle even the well-educated continue in a complete fog as to things which are simple in them- selves, and ought to be understanded of the people without difficulty. How far the book in question fulfils this want is a point on which opinions may differ. It is dedicated to the memory of Prof. Morris, and a very good likeness of that best of all geological teachers faces the title-page. Not the least valuable part of this little work consists of the Preface and Introduction, which are full of inducements to pursue the study of geology. When we come to the dry bones of the subject, then a text-book is a text-book, whether it be long or short. On the whole, the author places before his readers a consider- able amount of matter of a useful kind within the space allotted to him, though he makes a slip here and there. As, for instance, at page 41, where he is rash enough to give a formula for orthoclase which would yield less than 24 per cent. of silica in a mineral con- taining over 64 per cent. He is especially strong in dealing with physical features, and his great experience in connection with geolo- gical excursions renders this part of his subject comparatively easy to him. We sincerely trust that his ability and enthusiasm may gain many converts to the good cause. W. H. H. V.—Free Pusric Lrsraries, THEIR ORGANIZATION, USsEs, AND Manacement. By T. Greenwoop, F.R.G.S.. pp. 3820, Illus- trated. (Simpkin, Marshall & Co., 1887.) | eee though nominally only a fresh issue, is in fact a new edition of the volume which first appeared in 1886. It is printed in a handier form, has undergone revision, and the subject-matter has been re-arranged. The work ‘does not seek to be a book of instruction to those in charge of Free Libraries,” but is intended to further the extension of the Free Library movement and to aid those who are seeking to secure the adoption of the Libraries’ Act in their district by furnish- ing advice how to initiate and how to carry out the undertaking. A chapter is devoted to ‘‘Museums and Art Galleries,”—and another to “ Science and Art ”—*“ in connection with Free Libraries ;”’ but though “Commercial Museums” and ‘Technical Education ” have each their paragraphs, minerals and geological collections have Reports and Proceedings—Geological Society of London, 327 only an accidental allusion in one case—when the Ipswich Museum and Library are spoken of. Surely some knowledge of Geology, using that term in its widest sense, is both of educational value and technical importance in every district, to say nothing of its extreme usefulness in mining and agricultural centres, and we trust that Mr. Greenwood will in future editions be able to say something in favour of the study of that science which next to chemistry has the greatest influence over the affairs of our every-day life, and thus supply what, to us, seems the one omission in his admirable volume. cee @Oievoe SAN) a ee @ Cree eG Se ———————— GEOLOGICAL Society oF Lonpon. I.—May 9, 1888.—W. T. Blanford, LL.D., F.R.S., President, in the Chair.—The following communications were read :— 1. “The Stockdale Shales.” By J. E. Marr, Esq., M.A., Sec.G.S., and Prof. H. A. Nicholson, M.D., D.Sc., F.G.S. The Stockdale Shales extend in an E.N.E.-W.S.W. direction across the main part of the Lake District, parallel with the under- lying Coniston Limestone Series and the overlying Coniston Flags, with both of which they are conformable. 'They also occur in the neighbourhood of Appleby, and in the Sedbergh district. They are divisible into a lower group of black and dark grey and blue Grap- tolite-bearing shales, interstratified with hard bluish-grey mud- stones containing Trilobites and other organisms, and an upper group of pale greenish-grey shales, with thin bands of dark Grap- tolitic shales. The lower group (Skelgill Beds) are well seen in the stream which runs past Skelgill Farm, and enters Windermere near Low Wood; while the upper group (Browgill Beds) occurs fully developed in the Long Sleddale Valley, and its beds are very fossiliferous in Browgill. The authors divide these shales into a series of fossil-zones in the following order :-— BS 2 Upper { Bb 1 ( Browgill Beds { Ba 2 zone of Monograptus crispus. — IBaplaen. 55 ‘5 turriculatus. ( Aci ,, Rastrites maximus. Stockdale lee 4 -,, ,, Enerinurus punctatus. {Ab1 ,, Monograptus fimbriatus. Aa 2 Dimorphograptus confertus. Lower 22 . : . ( Aal Diplograptus acuminatus and Atrypa flexuosa. Of these zones, the lowest varies, occurring as a thin Limestone 328 Reports and Proceedings— in Skelgill, with Atrypa flexuosa, n.sp., and as Graptolitic shale at Browgill with Diplograpius acuminatus, Nich. 'The others appear to run persistently across the district, with the exception of the zone of Rastrites maximus, which has only been discovered in the Sedbergh area. The thicknesses, lithological characters, and fossil contents of these zones were considered, and comparisons made between these beds and the corresponding deposits of other areas. The whole group attains a thickness of from 250 to 400 feet, of which the Skelgill beds usually make up about one quarter. The authors correlate the Graptolite-zones with those of the Birkhill and Bala groups of Professor Lapworth as follows :— Laxe Disrricr. SoutH oF ScoTLanD. Zone of Monograptus crispus ...... = Zone of UW. exiguus. pp >, lurriculatus ......0.. Not separated. 9, LRastrites MAXIMUS......4.. = Zone of R. maximus. », Monograptus spinigerus \ ial > Monograptus spinigerus. Monograptus Clingani band ...... Not represented? ..........ceeceees », Letalograptus cometa. Zone of Monograptus convolutus.. 5 ) argenteus,. } = » WL. gregarius. 6 Jimbriatus. 35 Dimon “phogr aptus confer tus = » Diplograptus vesiculosus. Diplograptus acuminatus... = D. acuminatus. ” grap ” The zones of M. convolutus, M. argenteus, and M. fimbriatus contain abundance of M. gregarius, and the zone of Dimorphograptus confertus also contains Diplograptus vesiculosus in considerable numbers. The beds were also compared with the corresponding beds in Sweden, Bohemia, Bavaria, etc., and the fossils other than Grapto- lites were shown to occur elsewhere in strata of Llandovery- Tarannon age, from which it was concluded that the Stockdale Shales occupy that horizon. A fault occurs everywhere between the Middle and Lower Skelgill Beds, except perhaps in the Sedbergh district ; but it does not seem to cut out a great thickness of rock, and the authors gave reasons for supposing that it was produced by one set of beds sliding over the other along a plane of stratification. The beds are found to thicken out in an easterly direction, and the possibility of the existence of land in that direction was suggested. The authors directed attention to the importance of the Graptoli- toidea as a means of advancing the comparative Some of the stratified deposits of Lower Paleozoic age. A description was given of the following new species and varieties :— Phacops elegans, Boeck & Sars, var. glaber, Cheirurus bimucronatus, Murch., var. acanthodes, Cheirurus moroides, Acidaspis erinaceus, Harpes judex, H. angustus, Ampyx aloniensis, Proétus brachypygus, and Atrypa flexuosa. 2. “On the Eruptive Rocks in the Neighbourhood of Sarn, Caer- narvonshire.” By Alfred Harker, M.A., F.G.S. The rocks in question occupy an area about 53 miles long from north to south and 21 miles broad near the south-western extremity of Caernarvonshire. They were described by the author under the following heads :— (i.) Granite occupying the northern and north-western part of Geological Society of London. 329 the district. The ordinary type is a fairly normal biotite-granite ; but a variety at Meillionydd shows an exceptional structure, the biotite moulding the other constituents in ophitic fashion. The granites are intrusive in the Arenig shales. (ii.) Gabbro, diorite, etc., in two small patches only. The rock, originally a gabbro, passes into diorite, the diallage becoming am- phibolized, and the iron-ores disappearing with the production of granular sphene. Near a bounding-fault this hornblendic rock becomes locally schistose and gneissic. (iii.) Diabase, in the centre, forming the mass of Mynydd-y- Rhiw, and occurring in dykes and sheets near Sarn. (iv.) Hornblende-diabase showing various relations between the augite and hornblende. Besides the conversion of the former mineral to the latter, a closely similar hornblende has grown as an original border to augite-nuclei. The ‘‘ secondary-enlargement ” of hornblende-crystals is also exhibited. (v.) Hornblende-picrite in several varieties, forming stratiform banks to a thickness of 250 feet, and surmounted by hornblende- diabase. The two rocks seem to be in close relation to one another, and to have been injected as laccolites between the Upper Arenig strata near Penarfynydd and Rhiw. (vi.) Dolerite-dykes cutting all the other rocks, and probably Post-Carboniferous and Pre-Permian. With the exception of the last, all these rocks were referred, on such evidence as is available, to the Bala age. Il.—May 28, 1888.—W. T. Blanford, LL.D., F.R.S., President, in the Chair.—The following communications were read :— 1. “On the Spheroid-bearing Granite of Mullaghderg, Co. Donegal.” By Frederick H. Hatch, Ph.D., F.G.S. Communicated with the permission of the Director-General of the Geological Survey. This paper deals with a remarkable variety of granite which may be compared with the well-known orbicular diorite or Napoleonite of Corsica. According to Mr. J. R. Kilroe, of the Geological Survey of Ireland, who first discovered this interesting rock, the concretionary balls occur in close juxtaposition in a mass of granite of 5 or 6 cubic yards in size. They have not been found in any other portion of the granite area. The author first gave a detailed description of the microscopic structure of the normal granite. It is a coarse-grained rock, com- posed essentially of quartz, orthoclase, microcline, oligoclase, greenish hornblende and black mica. Sphene is an accessory constituent. Since it contains no white mica, the rock belongs to that subdivision of granite which has been termed granitite. A description of the spheroidal bodies was then given. The balls are somewhat flattened, the greatest diameter being, in one case, 4 inches, the smallest 9. Hach ball consists of two distinct parts, a pinkish central portion (the nucleus) and a dark-coloured peripheral or zonal portion (the shell). The nucleus consists of an irregular granitic aggregate of oligoclase felspar with a little interstitial quartz. The peripheral 330 Reports and Proceedings— shell is composed chiefly of oligoclase, but also contains abundant included plates of biotite, and over 12 °/, of magnetic iron-ore. It is to the presence of the last-mentioned mineral that the zonal portion owes its dark colour. By means of a Sonstadt’s solution the oligo- clase was isolated and analyzed with the following results :— SiO, = 60:99 Al,O3 = 25°56 CaO = 4°88 Na,O =. 7°48 Loss on ignition = “84 100°00 Sp. Gray 520492 This is the composition of an oligoclase of the formula Ab,An. The felspar of the zonal portion is disposed radially, the iron-ore radially and concentrically, while the mica appears to obey no fixed law of arrangement. A synopsis of the literature concerning the occurrence of similar concretionary bodies in granite was then given, the following authors being referred to:—Leopold v. Buch, Gustav Rose, Allnaud, Char- pentier, Jokély, von Andrian, Zirkel, G. W. Hawes, M. de Kronst- schoff, J. A. Phillips, vom Rath, Fouqué, Halst, Brogger, and Backstrom. The conclusion the author arrived at from a consideration of the subject was, that concretionary bodies occurring in granite, may, according to the mode of arrangement of their constituents, be divided into three classes, viz. :— 1. The concretionary patches of Phillips. 2. The granospherites of Vogelsang. 3. The belonospherites of Vogelsang. The spheroids from Mullaghderg belong to the last-mentioned class. They must be regarded as concretions formed, during the consolidation of the granite magma, by a process of zonal and radial crystallization around an earlier-formed nucleus. 2. “On the Skeleton of a Sauropterygian from the Oxford Clay, near Bedford.” By R. Lydekker, Esq., B.A., F.G.S. A description was given of a considerable portion of the skeleton of a Sauropterygian from the Oxford Clay of Kempston, consisting of several upper teeth, most of the mandible (of which the symphy- sial region is entire), a considerable number of vertebra mainly from the “pectoral” and dorsal regions, the greater portion of the two pelvic, and fragments of the pectoral limbs, and a considerable proportion of the pectoral and pelvic girdles. 'These remains were referred to Plesiosaurus philarchus, Seeley, and the various parts described in detail. The author discussed the advisability of retaining the forms de- scribed by various generic names by Professor Seeley, under the name of Plesiosaurus, and stated his intention of employing the latter term in its widest sense for the present. With this definition, the form under consideration was shown to present characters inter- 1 By difference. Geological Society of London. 381 mediate between those of Plesiosaurus and Pliosaurus, but was retained provisionally in the former genus. Although a direct link in the chain connecting the two genera, P. philarchus was not regarded as an ancestor of Pliosaurus, since teeth undistinguishable from those of the latter genus occur in the Coralline Oolite. Finally it was concluded that the evidence brought forward was sufficient to render necessary the abolition of the name Pliosauride, and the inclusion of Plesiosaurus and Pliosaurus in a single family. 3. “On the Hozoic and Paleozoic Rocks of the Atlantic Coast of Canada in comparison with those of Western Europe and the Interior of America.” By Sir J. W. Dawson, LL.D., F.R.S., F.G.S. The author referred to the fact that since 1845 he had contributed to the Proceedings of the Geological Society a number of papers on the geology of the eastern maritime provinces of Canada, and it seemed useful now to sum up the geology of the older formations and make such corrections and comparisons as seemed warranted by the new facts obtained by himself, and by other observers of whom mention is made in the paper. With reference to the Laurentian, he maintained its claim to be regarded as a regularly stratified system probably divisible into two or three series, and characterized in its middle or upper portion by the accumulation of organic limestone, carbonaceous beds, and iron- ores on a vast scale. He also mentioned the almost universal pre- valence in the northern hemisphere of the great plications of the crust which terminated this period, and which necessarily separate it from all succeeding deposits. He next detailed its special develop- ment on the coast of the Atlantic, and the similarity of this with that found in Great Britain and elsewhere in the west of Europe. The Huronian he defined as a littoral series of deposits skirting the shores of the old Laurentian uplifts, and referred to some rocks which may be regarded as more oceanic equivalents. Its characters in Newfoundland, Cape Breton, and New Brunswick were referred to, and compared with the Pebidian, etc.,in England. The questions as to an Upper Member of the Huronian or an intermediate series, the Basal Cambrian of Matthew in New Brunswick, were discussed. The very complete series of Cambrian rocks now recognized on the coast-region of Canada was noticed, in connexion with its equi- valency in details to the Cambrian of Britain and of Scandinavia, and the peculiar geographical conditions implied in the absence of the Lower Cambrian over a large area of interior America. In the Ordovician age a marginal and submarginal area existed on the east coast of America. The former is represented largely by bedded igneous rocks, the latter by the remarkable series named by Logan the Quebec Group, which was noticed in detail in connexion with its equivalents further west, and also in Europe. The Silurian, Devonian, and Carboniferous were then treated of, and detailed evidence shown as to their conformity to the types of Western Europe rather than to those of America. In conclusion, it was pointed out that though the great systems of formations can be recognized throughout the Northern Hemisphere, 332 Correspondence—MUr. A. J. Jukes-Browne. their divisions must differ in the maritime and inland regions, and that hard and fast lines should not be drawn at the confines of sys- tems, nor widely different formations of the same age reduced to an arbitrary uniformity of classification not sanctioned by nature. It was also inferred that the evidence pointed to a permanent con- tinuance of the Atlantic basin, though with great changes of its boundaries, and to a remarkable parallelism of the formations deposited on its eastern and western sides. 4. “On a Hornblende-biotite Rock from Dusky Sound, New Zealand.” By Captain F. W. Hutton, F.G.S. The rock is of eruptive origin, and is associated with Archean schists and gneisses. It is compact, crystalline, of a dark-green colour, and sp. gr. 8: 00—3:07. It is composed of two minerals in nearly equal proportions, one of which, a black mica, has the two optic axes nearly coinciding. The other mineral is of a pale bluish- green colour, and moderately dichroic ; it shows an aggregate polari- zation of rather coarse grains, with here and there distinct crystals of considerable size. Often one side of a crystal shows a single twin, while the other side is polysynthetic. The optical characters are those of the monoclinic system, and further investigation proves these crystals to be hornblende. The mineral which shows aggregate polarization is either crushed hornblende or some altered form of it. CORRESPONDENCE. ——E———— THE CORRELATION OF MIDLAND GLACIAL DEPOSITS WITH THOSE OF LINCOLNSHIRE. Str,—It is certainly very desirable that the Glacial Deposits should be correlated with one another, but I do not think any reliable results will be obtained by comparing the descriptions and conclu- sions which have been published by Mr. Deeley and myself. We have necessarily looked at the beds from different points of view, and I had hoped that Mr. Deeley would have made himself person- ally acquainted with the tract which lies between the areas we have respectively studied before suggesting anything in the way of cor- relation. He thinks that his classification into Older, Middle and Newer Pleistocene might be adopted for Lincolnshire, though the only “Older Pleistocene”? deposit known to him in that county is the quartzose sand of Gelston. He suggests, however, that some of the clays classed by me as Newer Glacial may really be older than the Chalky Boulder Clay, and he apparently finds great difficulty in accepting the occurrence of such Newer Glacial Beds at elevations approaching 400 feet. I will only reply that there are many places where he may walk from the eastern plain to the top of the Wold over a continuous sheet of the same kind of Boulder Clay ; but when Mr. Deeley can record any facts which seem to support his idea, I shall be quite ready to discuss thei. As regards the Gelston Sand, I must point out that this is an out- lying patch, and there is no local evidence to show whether it is older Correspondence— Prof. Edward Hull. 033 or newer than the Boulder-clay east of Grantham. Mr. Deeley regards it as older because the material is similar to that of his older Pleistocene sands ; he may be right, but neither I nor my colleagues have found any deposits elsewhere in Lincolnshire which could be regarded as distinct from, and older than, the great chalky Boulder- clay. The only locality where any great mass of Glacial gravel exists is around Benniworth, near Donnington, and this will be described in the forthcoming memoir on Sheet 83 of the Geological Survey Map. There, if anywhere, will Mr. Deeley find the analogue of his Older Pleistocene ; but J very much doubt whether clays containing Pennine detritus ever extended so far to the east. If any Older Pleistocene deposits existed in Hast Lincolnshire, I should expect them to be rather of the Cromer than of the Pennine type. With regard to the marine origin of the Newer Glacial clays, I would call attention to the remarkable deposits near Kirmington in North Lincolnshire, where laminated loams and sands containing perfect shells are associated with Boulder-clay of the Hessle type in such a way as to lead to the conclusion that they all belong to one group. These beds were carefully studied by Mr. C. Reid, and it is to be hoped that a description of them may soon be published. The most surprising statement in Mr. Deeley’s article is that many geologists regard the glaciated surfaces beneath the Drift of Lancashire as caused by large icebergs grating along the bottom of a sea about 1200 feet deep! He must have strangely misunderstood the views of those who believe the strize to have been caused by sea-ice, and surely a little consideration will enable him to see that every single striated surface might have been glaciated in shallow water during the progress of a gradual submergence. I certainly never heard of any one who supposed that no such action occurred till the water was 1200 feet deep. Mr. Deeley has done good work in the Midlands; let me recommend him to take his note-book into Lincolnshire, and when he publishes his observations, to keep his facts rigidly apart from his theories. Surrtey, Souruampron. A. J. JuKres-Browne. DISCOVERY OF LOWER CARBONIFEROUS BEDS IN UPPER EGYPT. Sir,—The discovery of Lower Carboniferous beds in the wild region between the Nile and the Gulf of Suez adds a new feature of interest to the Geology of Egypt. The announcement is contained in a memoir by Dr. Schweinfurth, of Cairo, of which he has been kind enough to forward me a copy containing the result of an ex- ploration by himself and M. Walther, of Jena, into the valley of the Arabah, and communicated to the Egyptian Institute.’ At first I was somewhat startled by the title and the early pages of the memoir, as the members of the Expedition of the Palestine Exploration Society (1883—4) had failed to notice any Carboniferous beds in the Wadi Arabah, at the head of the Gulf of Akabah, until we lighted upon 1 «Sur une récente Exploration Géologique de l’Ouadi Arabah,” Le Caire, 1888. O34 Correspondence—Prof. J. Prestwich. them at Lebrusch, on the flanks of the Moabite hills above the shore of the Dead Sea. I supposed, therefore, that Dr. Schweinfurth had found what we had failed to notice. But, on reading further, the matter was set at rest. It is somewhat unfortunate, and tending to confusion, that there are two Arabah valleys, one in the eastern part of upper Egypt, opening out on the Gulf of Suez, and the other con- necting the Gulf of Akabah with the Dead Sea and Jordan Valley. The former is that referred to by the African explorer, and is of special importance as helping to connect the geology of the Upper Nile Valley with that of Arabia Petreea. Dr. Schweinfurth recog- . nizes the identity of the beds he describes with those of the Wadi Nasb in the Sinaitic Peninsula, where limestone containing fossils of Carboniferous Limestone age, first discovered by Mr. Bauerman, are interposed between crystalline rocks and sandstones and other strata of Cretaceous age. These beds were afterwards examined by Col. Sir Charles Wilson and by the Members of the Expedition of 1883—84, and the fossils brought home by them were determined by Prof. Sollas.' Of this identification of the beds of the Wadis Nasb and Arabah there can be no question, as the genera of the fossils are in most cases identical, and the species characteristically Carboniferous. The following is a section of the beds in the escarpment of the southern flank of the plateau of north Galala, descending to the bottom of the Wadi Arabah, in Upper Egypt, as given by Dr. Schweinfurth :— Summit of Escarpment ; 1400 m. above the sea. 300 m.—Terraines Tertiaires du Parisien. 200 m.—Terraines Tertiaires Londinien (?). 200 m.—Banks of débris covering Cretaceous-beds of Stages Up. and Lr. Senonien, 50 m.—Argillaceous and Marly ochreous Limestone and sandy beds with Ammonites. Senonien inferieur. 250 m.—Escarpment of red Nubian Sandstone. (TZerrains Crétacés d incertains étages). (Geat Geological hiatus. ) 2m.—Dark Sandstones with silicified wood (Araucarioxylon). Lower Carboni- JSerous. 60 m.—Solid and soft Sandstones and Marls, with fragments of Crinoids, and Spirigera. 1 m.—Bed of hard blue Limestone—with Crinoids, Productus, Spirifer, etc.— (Carboniferous Limestone). 40 m.—Marls and Sandstone partly fossiliferous. Lower Carboniferous. (Details of beds below this not given.) GzoLocicaL SurvEY Orricr, Dusiin, 23 May, 1888. E. H. THE ATMOSPHERE OF THE COAL PERIOD. Str,— From the silence of your reviewer, I presume that he is unable to verify the assertion so often made that experiments had proved the improbability of plants living in an atmosphere contain- ing an excess of carbonic acid. As I before remarked, very few definite experiments had been made besides the one I have quoted in my work. I might, however, have referred to those made by 1 <« Physical Geology of Arabia Petreea and Palestine,’’ Mem. Palestine Exploration Fund, p. 48. Correspondence—Mr. W. W. Watts. 335 Daubeny in his Reports to the British Association 1847—1850, “On the Influence of Carbonic Acid Gas on the Health of Plants, especially to those allied to two Fossil Remains found in the Coal- formation.” These, although wanting in definite measures and not embracing the whole field of inquiry, are of great value so far as they go, as they confirm at all events the possibility of the original suggestion of Brongniart with respect to the condition of the atmo- sphere during the Goal Period. Daubeny showed that Lycopodium continued during five weeks in perfect health in an atmosphere containing 5 per cent. of carbonic acid, though species of Adiantum appeared less thriving than the corresponding plants not so treated, but that 20 per cent. of carbonic acid proved injurious in two or three days. He also found that Frogs and Newts did not appear to suffer in an atmosphere containing 5 per cent. of the gas. This, however, is a proportion quite excessive and perfectly unnecessary for the object in view, and is therefore beyond the mark. Nevertheless, Daubeny came to the conclusion that the general tenor of his experiments justified him ‘in inferring that there is nothing in the organization of those plants and animals of the present day which appear most nearly allied to such as were in existence during the Carboniferous epoch, or even somewhat subsequent to that period, militating against the probability, that a larger amount of carbonic acid may have been present in the atmo- sphere and diffused throughout the waters of the sea and rivers, than is found either in the one or the other at the present time; nor is there anything to prevent us from imagining that the absorption of carbon by vegetables and the consequent rapidity of their growth may, at least within certain limits, have borne some proportion to the greater amount of carbonic acid assumed to have been present at earlier periods in the history of our globe.” JosEPH PRESTWICH. THE GEOLOGY OF MYNYDD MAWR. Sir,—I have been much interested in Mr. Harker’s description of the rocks of Mynydd Mawr and the Nantlle Valley. His observations on the cleavage structure round the intrusion point it out as a great “eye,” whose main axis runs parallel to the cleavage of the district. Last year, while endeavouring to work out the structural relations of the mass, I paid considerable attention to all the junctions, especially those along the §.H. flank. These are everywhere of an obviously intrusive character, the ‘“‘ quartz-porphyry ” frequently transgressing upon the bedding of the slates. The main difficulty about the junction to me was that in some places the slates dipped under the intrusive mass, while in others they dipped off it. But I found one section in which the bedding rose vertically, and then bent outwards at an angle of 45°, the porphyry in the upper part resting on the slate. Probably this relation of the two rocks frequently exists round the hill, the lines of rock flowing (if we may use the term) round the intrusion not only in a horizontal but also in a vertical direction. University Museum, Oxrorp. W. W. Warts. 336 Correspondence—Ir. 8S. S. Buckman—WMr. C. D. Sherborn. ‘PALAONTOLOGICAL NOMENCLATURE, Srr,—Mr. Jukes-Browne and myself are as wide asunder as the poles in our wishes with regard to Ammonites; nor does he agree with Mr. Haddow in his method of using the trinomial system. As I cannot defend my numerous sins without asking for more space than the subject warrants, I will only notice one or two points. I did not know the form of the mouth was so potent a factor among Ammonites. My method is to try and trace out step by step the descent of each species, and to arrange them accordingly. I shall not place in one and the same genus two species of Inferior Oolite Ammonites, one of which has descended, say, from a Lower Lias Afgoceras, and the other from a Lower Lias Arietites, however similar they may be in mouth or otherwise, although Mr. Jukes- Browne thinks it would not be wrong. I disagree; and so the same genus will not include the descendants of two distinct genera. T agree with Mr. Jukes-Browne that, instead of amplifying an old system, it had been better to start afresh. The MS. to correct this has been written some time. Still his objection overshoots the mark. No one, I imagine, in naming the Sparrow would begin with Aves and end with Insessores, Conirostres, Fringillide, Passer domesticus. Mr. Jukes-Browne does not answer the point of my question, viz. about cornu, and does not attempt Lioceras. STONEHOUSE. S. S. Buckman. PARKINSON’S ‘‘ORGANIC REMAINS.” §rr,—Can you or any of the readers of the GronocicaL Magazine tell me the date of the sale of the Collection of Fossils formed by James Parkinson, the author of ‘Organic Remains,” as I wish to find some account of this sale in the literature of the time. From an examination of the ‘‘Sowerby Mineral Conchology ” collection in the British Museum of Natural History, I am led to suspect that some of Parkinson’s fossils had already been acquired by Sowerby, and if this really is so, these specimens will have a double interest. C. Davies SHERBORN. 540, Kine’s Roan, S.W., 21sé June, 1888. THE GEOLOGICAL MAGAZINE. NEWO SERIES, DEGADE Ill; “VOE. NV. No. VIII.—AUGUST, 1888. QrigIE MENA, ANSARI G sis I.—Tue Jorpan-ARABAH DEPRESSION AND THE DEAD SEA. > By Israzt C. RussExx, Of the United States Geological Survey (Appalachian Division of Geology), Department of the Interior, Washington, D.C., U.S.A. \HE following account of the geology of the Dead Sea basin has been compiled from the observations of others, and I am especially indebted in this connection to H. J. Johnson, Geologist of the United States Expedition to the Dead Sea,! to Professor Louis Lartet, Geologist of the Duc de Luynes’ Expedition to the same region,? and to Prof. Edward Hull, F.R.S., Director of the Geological Survey of Ireland, who visited Arabia Petrea and Palestine in 1883-84, under the auspices of the Committee of the Palestine Exploration Fund.’ Besides these observers, who devoted their attention specially to the geology of the regions traversed during 1 This Expedition visited Palestine in 1848, under direction of Lieut. W.S. Lynch. Among its more important contributions to science was the measurement, by means of the spirit level, of the depression of the surface of the Dead Sea below the level of the Mediterranean, the exploration of the River Jordan from the Sea of Galilee to its mouth, and the determination, by sounding, of the depth of the Dead Sea. The results of this Expedition were published in ‘‘ Official Report of the United States Expedition to the Dead Sea and the River Jordan,”’ by Lieut. F. W. Lynch, U.S.N., Baltimore, 1852; 4to. pp. 1-236, pl. 17, and a map. Also in “Narrative of the United States Expedition to the Dead Sea,” by F. W. Lynch, U.S.N., Philadelphia, 1849; Svo. pp. 1-xx, 1-508, pl. 28, and two maps. 2 This Expedition, fitted out and directed by the Duc de Luynes, visited Palestine and the adjacent regions in 1864; its scientific results include important contribu‘ions to geology and paleontology, and a study of the chemistry of the waters of the Dead Sea. Preliminary publications of the results of Louis Lartet’s observations while connected with this Expedition, appeared in the ‘‘ Annales des Sciences Géologiques” for 1869 and 1872.- The final report is: ‘‘ Voyage d’ Exploration a la Mer Morte,”’ par M. le Duc de Luynes, Tome ‘Troisiéme, “‘ Géologie’’ (Paris, 1877), 4to. pp. i-vi, 1-326, pl. 1-14. ’ The report of the geological observations made during this Expedition has recently appeared, and is an important and highly interesting contribution to geological science. Its title is: ‘‘ Memoir on the Geology and Geography of Arabia Petra, Palestine, and adjoining districts.”” Published for the Committee of the Palestine Exploration Fund, London [?], 1886. 4to. pp. i-viii, 1-144, pl. 3, and three maps. A narrative of this expedition by the same author, scarcely less important than the final report, is entitled: ‘‘ Mount Seir, Sinai, and Western Palestine, being a narrative of a scientific expedition,” 1883-84, London, 1889. 8yo. pp. 1-vi, 1-227, pl. 1-13, and two maps, DECADE III.—VOL. V.—NO. VIII. 22 838 JI. O. Russell—The Jordan-Arabah and the Dead Sea. their several expeditions, the writer is under obligations to the Ordnance Survey of Palestine, and to many observant travellers, including Condor, Fraas, Tristram, Wilson, and others, for many interesting details and attractive descriptions concerning the regions to which it is desired to direct the reader’s attention. The similarity between the recent geological history of the Dead Sea, and the area of interior drainage in America known as the “Great Basin,” with which I have some familiarity, is so marked that I venture to offer a few suggestions and hypotheses, which will, perhaps, be of interest to those who may continue the study of the Geology of Palestine and adjacent regions. I have also inserted a brief account of certain lake-shore phenomena, which have proved of great value in interpreting the ancient histories of several American lakes, which are comparable in many ways with the Dead Sea. Physical Geology of the Dead Sea Region. On the west side of the abrupt valley in which the Sea of Galilee, the valley of the Jordan, the Dead Sea, and the Wady Arabah— termed the Jordan-Arabah depression—are situated, lies the table land of Judea, and the extension southward of the same physical feature known as the plateau of the Tih. The general elevation of this extensive table land is about 2000 feet above the Mediter- ranean, with occasional eminences attaining a height of from 2500 to 8000 feet. On the east it breaks off in an abrupt escarpment, which forms the western boundary of the Jordan-Arabah depression. This depression is bounded on the east by an escarpment still more rugged and of a greater elevation than on the west. The eastern wall, like the western, exposes the edges of strata which form a vast plateau, known east of the Jordan as the table land of Moab, having a general surface level of about 38000 feet, and farther south as the table land of Edom, the general elevation of which is about 4000 feet above the ocean. The Moab-Edom plateau stretches far to the eastward, with but little change in its physical features, and merges with the Syrian and Arabian deserts, but is not again broken by a sunken area similar to that holding the Dead Sea. The depression separating the plateaux we have mentioned is from five to nine miles broad, and extends in an approximately north and south direction from the base of Mount Hermon at the north to the Red Sea at the south, a distance of fully 875 miles. Its southern end is occupied for about 100 miles by the waters of the Gulf of Akabah. The length of the Jordan-Arabah depression proper is nearly 250 miles, its southern terminus being at the water- shed between the Wady Arabah and the drainage which finds its way toward the Gulf of Akabah. Considering general features simply, there are two elevated table lands in the south-western part of Asia Minor, separated by a deep, narrow depression or fault valley, which is partially filled by the Dead Sea. I. O. Russell—The Jordan-Arabah and the Dead Sea. 389 Origin of the Jordan-Arabah Depression. The observations of Hull, Lartet, Tristram, and others, have shown that this depression has been produced by a fault. In other words, it is due to a fracture in the rocks forming the adjacent table lands, accompanied by a subsidence of the strata on the west side of the fracture in relation to the broken edges of the corresponding beds on the east. The amount of this displacement is not accurately known, and no doubt varies at different portions of the fault line, but is certainly several thousand feet. Judging from the sections published by Hull, 5000 or 6000 feet would be a reasonable minimum estimate. This great fracture follows the base of the escarpment bordering the Jordan-Arabah depression on the east, and passes beneath the Dead Sea near its eastern shore. Its full linear extent is not known, but it has been traced by Hull and others for perhaps 150 miles. Its course is somewhat irregular, and numerous branches or secondary faults are connected with it, but its general bearing throughout its entire course is a few degrees east of north. The hade of the fault plane has not been definitely determined at any locality so far as we can ascertain, but is repre- sented in sections published by various geologists as dipping toward the thrown block at a high angle; that is, it is considered as a normal fault, in distinction from reversed faults, in which the hade is toward the upthrow. The strata composing the plateaux adjacent to the Dead Sea fault have been but little disturbed except in proximity to the line of fracture, and over large areas are nearly horizontal. The rocks forming these plateaux are Cretaceous limestones and sandstones, resting on rocks of the Carboniferous system, which in their turn are underlain by metamorphic strata perhaps of Archean age, together with igneous rocks of ancient but unknown date. Besides these older formations there are, especially in the neighbourhood of the Sea of Galilee, volcanic dykes and overflows of basaltic lava that are geologically recent. The formation of the Jordan-Arabah depression, although due to a violent fracturing of the earth’s crust, cannot be considered as having been formed suddenly at a single great catastrophe, but, judging from what we know of the formation of similar faults in other regions, must have been of slow growth, accompanied by many earthquakes, and may perhaps be still increasing its displacement. The numerous earth tremors felt in Palestine during the present century may possibly owe their origin to slight slips along this line of fracture. Lakes in the Dead Sea Basin. The lacustrine history of the Dead Sea basin began with the time when the fault to which it owes its origin had gained sufficient dimensions to interrupt the previous drainage of the region. This statement is made on the supposition, in the absence of evidence to the contrary, that the south-western part of Asia Minor was a land surface at the time the fault was initiated. 340 J. C. Russell— The Jordan-Arabah and the Dead Sea. The date of the beginning of this independent drainage system is not definitely known. It was post-Cretaceous, for the reason that Cretaceous rocks form its walls. That it existed as a prominent topographic feature previous to the Glacial epoch is shown by its lacustrine records, taken in connection with the history of adjacent regions during the Quaternary period. Its birth must therefore have been during the Tertiary period. The best estimate that can be made at present of the extent of the hydrographic basin of the Dead Sea shows that it occupies an area of between nine and ten thousand square miles. The Dead Sea is about 274 square miles in extent.? Consequently the ratio of lake surface to drainage area is about as one to thirty-three. The lowest point in the basin is depressed 2570 feet below the level of the Mediterranean, and the lowest point on its rim is 285 feet above the same datum plain, or 1577 feet above the surface of the Dead Sea. It is evident from the present topography that this hydrographic basin must have held a lake in its lowest depression, either continuously or at intervals during humid periods, ever since it was cut off from oceanic drainage. A lake occupying the Jordan-Arabah depression, like all inclosed lakes, must have been sensitive to climatic changes, and could its past fluctuations be determined in terms of climate, they would furnish a geological weather record of unusual value. In illustration of this it may be observed that as the present arid climate of the Dead Sea basin admits of the existence of a large lake in its lowest depression, it follows that only during periods of excessive aridity could the ratio of evaporation to precipitation be increased suffi- ciently to cause the lake to disappear. 1f we could show, therefore, that the Dead Sea was evaporated to dryness, or was greatly con- centrated, at any period in its history, we should have proof of the former prevalence of an unusually arid climate in Palestine and adjacent regions. On the other hand, could we show that the Dead Sea once had a much greater expansion than at present, it would be conclusive evidence of a former period of greater mean bomidney than the region about it now enjoys. The fact that the Dead Sea basin has been long isolated is in itself sufficient to suggest that it has an interesting and perhaps highly complex lacustrine history. Fortunately, however, we have observation as well as hypotheses to help us in this connection. From the reports of many explorers we know that the shores of the Dead Sea and the borders of the Jordan valley are scored with terraces, and that lacustrine sediments, in some cases charged with the shells of fresh water mollusks and at other times inter- laminated with layers of salt and gypsum, are found over a very large area. Sufficient facts of this nature have been reported by competent observers to show that the Dead Sea basin has a record ' Hull places it at the close of the Eocene. Geol. and Geog. of Arabia Petrea, Palestine, etc., p. 108. 2 Determined from the map accompanying the narrative of the U.S. Expedition. The mean depth of the Dead Sea as obtained from the same map is 500 feet. I. C. Russell—The Jordan-Arabah and the Dead Sea. 341 of unusual interest inscribed on its walls, much of which is written in such bold characters that he who runs may read. Before considering the facts that are available in reference to the former climatic condition of Palestine, and the deductions which lecitimately flow from them, let us glance briefly at the nature of the records to be looked for, in order to interpret the lacustrine history of an inclosed drainage area of the nature of the Dead Sea basin. Lacustrine Records. Sea-Crirrs.—Waves breaking along a shore tend to undercut it and allow the material forming the land to fall from above. This process, as may be seen on every shore, produces a slope, more or less abrupt, which is termed a sea-cliff. The steepness of such slopes depends on the rate of cutting and on the nature of the material removed. When the work of the waves is rapid, and the shores are formed of material having a high angle of stability, perpendicular, or even over-hanging cliffs are produced. When the wave erosion at the base is less rapid than the atmospheric erosion at the top of a cliff, the slope is less abrupt. The height of cliffs produced in this manner varies from a few feet, or even a few inches, up to many hundred feet. Their bases are horizontal, and at the water line the rock is frequently eaten away irregularly, so as to form caves. Trrraces.—Waves and currents in cutting away the shores which confine them, remove the material brought within their reach, and as their work progresses landward, form a horizontal shelf or terrace. Such a terrace is bordered on the landward side by a sea-cliff which rises above it, and on the lakeward side by a downward slope, which is usually covered to some extent with debris, derived from the formation of the terrace itself. Terraces of this description are horizontal along the line where the shelf joins the sea-cliff, and slope from this line gently lakeward. When seen in profile, they appear as a notch more or less strongly defined on the slope confining the lake. Terraces frequently occur at many horizons on the shores of inclosed basins; their relative strength, other things being equal, being determined by the length of time the water lingered at each horizon. When the waters of a lake are withdrawn or greatly lowered, the records of their former levels appear from a distance especially when the shores are steep, as horizontal parallel lines, drawn on the borders of the basin. These lines follow all the irregularities and sinuosities of the shore, and are usually strongest and best defined on promontories and on coasts facing a broad water area. At the heads of sheltered bays, even in the case of lakes of great size, both terraces and sea cliffs are sometimes absent. A terrace of excavation, the formation of which we have just described, marks definitely the outline of the water surface to which it owes its origin. By following such a terrace one can ascertain if it was ever broken by a channel of overflow, and thus in the case of a desiccated lake basin, determine one of the most important points 342 I. C. Russell—The Jordan- Arabah and the Dead Sea. in its history. As a terrace when formed is level—with certain slight variations due mainly to the action of the wind in heaping up waters in bays, etc.—a measurement of its present relation to a horizontal plain will indicate whether or not it has been deformed by orographic movement. The terraces described in the preceding paragraph are terraces of excavation. In nature we find terraces of construction as well. These are formed of the debris cut away from the shore by waves and currents, and spread out as a belt of shingle along the shore, resting usually on a cut terrace. The combination of cut and built terraces is the most common of lake-shore records, and the most easily identified in abandoned lake-basins. The material removed from the shores of a lake during the cutting of its marginal terraces, together with much of the debris contri- buted from the land by streams, is removed more or less completely, and after being assorted by the action of waves and currents, is variously distributed. The finer portions remain in suspension for a considerable time, and may be carried away from the land, and on subsiding contribute to the sedimentation of the basin. ‘The coarser portions consisting of sand, gravel and boulders, are too heavy to be floated, and therefore remain in close proximity to the shore. This material is swept along the lake margin by currents, and finally built into beaches, barriers and embankments. Bracues.—In the formation of beaches the shore debris remains at the lake margin and may coincide with a built terrace, as pre- viously noted, or form a terrace along a shore where no excavation has taken place. In either instance the material composing the beach, usually gravel, is in motion, especially during storms, and is being carried forward to where barriers and embankments are forming. Barriers.—On lake margins of gentle declivity ridges of gravel and sand are formed at some distance from the shore, but connected at their extremities with terraces or beaches from which the material for their construction is derived. The surfaces of such ridges are horizontal and coincide with the storm limit of the waves and cur- rents to which they owe their origin. They follow the broader sweeps of lake margins but not minor irregularities, and in desiccated lake basins appear like railway embankments. They frequently close the mouths of bays so as to shut them off from communication with the main water body, thus forming lagoons. EMBANKMENTS.— When the combined action of waves and currents extends a barrier into deep water, an embankment is formed, which in many cases becomes of very grand proportions. In the formation of embankments the debris of which they are composed is swept along the surface of the barrier or terrace leading to them, and deposited when deep water is reached. This process continues until the embankment has been built up to the water surface. It is then prolonged by material carried along its crest and deposited at its distal extremity. Both bars and embankments, when seen in cross section, having a more or less well-defined anticlinal structure. An arch of this character is termed an “anticlinal of deposition.” The I. O. Russell—The Jordan-Arabah and the Dead Sea. 343 elevations of the horizontal surfaces of barriers and embankments, in the case of fossil lakes, furnish the most accurate of all shore records for determining former water levels. Detras.—A delta formed bya high grade stream, when seen in section, presents a well-marked tripartite structure. The middle member consists of water-worn gravel, more or less thoroughly assorted, in layers sloping lakeward at an angle corresponding with its angle of stability in water. The thickness of this deposit in- creases as the delta is advanced, and in lakes with precipitous borders may become several hundred feet deep near the lakeward margin. Beneath the inclined gravels, especially in the case of deltas that have been prolonged some distance into a lake, are lacustrine clays and marls, which are usually crumpled and otherwise deformed, owing to the weight of the mass of material superimposed upon them. Above the inclined gravel is a deposit of unassorted or irregularly assorted debris, which is thinnest toward the periphery of the delta and thickest towards its apex. The history of the growth of a delta may be inferred from its structure, and need not be described here. We have not attempted even a sketch of all the features of lake shores that are of assistance to the geologist in determining the history of a fossil lake, partially for want of space, but principally for the reason that an exhaustive analysis of lake-shore phenomena is already accessible to the student.’ MecuanicaL SeprMents AND CuemicaL Precrerrares.—The de- posits usually formed in lakes, as is well known, are evenly stratified clays and marls, which are in many instances charged with shells. When lakes are without outlet, however, and become saline owing to the concentration of their water by evaporation, their faunas are exterminated or greatly modified, and the mineral matter held in solution is precipitated when the process has progressed sufficiently. If concentration continues without interruption, there will be a regular sequence in the precipitates formed, beginning under normal conditions, with calcium carbonate, followed by calcium sulphate, sodium chloride and other salts. Chemical precipitates originating in the manner mentioned above may be deposited on the sides of a lake basin with rocks and stones for nuclei, as is the case very commonly with incrustations of cal- careous tufa; or they may be precipitated generally over the lake bottom and become mingled with clays and marls deposited simul- taneously. When sedimentation is taking place but slowly, layers of various salts may attain a depth of many feet, and should uniform conditions continue, may even become hundreds of feet in thickness. After the precipitation of saline deposits of this nature a lake might expand owing to a climatic change and be freshened either on account of the increase in supply, or by the waters rising sufficiently to find an outlet, and thus flood out the previously concentrated brine. In such instances the beds of calcareous tufa, gypsum and common 1 “The Topographic Features of Lake Shores,” by G. K. Gilbert, in Fifth Annual Report of the U. 8. Geological Survey, 1883-84, Washington, 1885. 344 9 A. C. Seward—Cyclopteris from the Coal-measures. salt precipitated during the period of concentration, might become buried beneath layers of marl and clay abounding in the remains of mollusks and fishes. With this imperfect lesson on what is taking place in lakes at the present day, let us return to the Dead Sea. (Lo be concluded in our next Number.) I].—Woopwarpian Museum Notes. On a Specimen or CyrcLopreris (Brongniart. ) By Apert C. Sewarp, B.A., F.G.S., Foundation Scholar of St. John’s College, Cambridge. (PLATE X.) HE specimen of which I give below a brief description is of some interest as adding to the store of facts which may help us in the elucidation of the obscure genus Cyclopteris. So far as I know such large Cyclopteris leaves have not been previously figured attached to a rachis. The described specimen, which I have placed in the Woodwardian Museum, was given to me by Mr. Walter Hemingway, of Barnsley, who found it in the Upper Coal-measures of Brierly Common, York- shire. When first seen’ the rachis was 4ft. 2in. long, and had five pairs of pinnules, the distance between each pair decreasing towards the thinner end of the rachis. Unfortunately it was impossible to get the fossil out whole, only two pairs of pinnules being obtained in a perfect state. Frond pinnate. Pinnules suborbicular; sessile ; apparently lobed at the base, the lobes resting on the rachis: the lower margin of the pinnules is somewhat abruptly cut off as if the present shape might be due to tearing or imperfect preservation, the original pinnule having probably a more rounded or tapering base. No midrib, the nervures radiate from the basal portion of the pinnules and frequently dichotomise as they proceed towards the margin, where they are delicate and numerous. The rachis is represented by a raised portion of the stone, which is finely striated longitudinally, the strie being somewhat irregular, and not continuous from one end to the other: a few isolated frag- ments of carbanaceous matter represent the original cortical tissues of the rachis. Length of rachis shown in figure 8 cm.; breadth 2 cm.; pinnules in longest part 7 cm.; greatest breadth 5 cm. The genus Cyclopteris established by Brongniart in 1828, is defined by him as follows:*—‘‘Fronde simple, entiére, le plus souvent orbiculaire ou réniforme ; nervures nombreuses toutes égales, dichotomes, rayonnant de la base.” The essential generic characters being the absence of a midrib, and the basal origin of the nervures. In the ‘“ Histoire des végétaux fossiles” * Brongniart figures several 1 T am indebted to Mr. Hemingway for these facts. 2 Prodrome d'une hist. des végét. foss. p. 51 (1828). 3 Hist. des yégét, foss. plates 61 and 61 bis. (1828-1837). eC 8 5 2 z ct a oy a & § doj[ox94 194 if ‘earys>pto A, ‘seansvey, [29°90 N (Bu0oig) s ‘dun og weave 399, “S881 SEN 1999 HMRI USIAN UME SAP ASSEN A. OC. Seward—Cyclopteris from the Coal-mcasures. 345 species of Cyclopteris, none of which exactly correspond to my specimen, Cyclopteris obliqua, which is represented as an isolated petiole, being the most like it. In his later work’ Brongniart divides the Cyclopteroid forms into two genera, Cyelopteris and Nephropteris: the former he defines as follows :—‘ Fronde simple, pédicellée, symétrique, arrondie, cordiforme, ou flabellée, entiére ou lobée, sans apparence de nervure médiane, toutes les nervures partant de la base du limbe, et se divisant en se dichotomant pour atteindre la circonférence.” Cyclopteris reniformis, C. trichomanoides, C. digitata, etc., belong to this genus. The genus Nephropteris which is thus defined :—‘“ Frondes isolées, simples, sessiles, obliques, non symétriques, arrondies ou cordiformes, ordinairement concaves et ombiliquées & leur base ”—includes such forms as Cyclopteris obliqua, C. oblata, C. orbicularis, etc. These species are regarded by Brongniart as a distinct group ; he considers them to be anomalous basal leaves, referable probably to the genera Neuropteris and Odontopteris. Lindley and Hutton? give two figures of Cyclopteris obliqua; they point out that the absence of any stalk and the trace of what seems to them a distinct disarticulation favour the idea that the specimens originally formed parts of compound leaves. This being the case, they consider them referable to Neuropteris rather than Cyclopteris. It is also suggested by these authors® that Neuropteris ingens may have belonged to the same plant as Cyclopteris obliqua. In the “Illustrations of Fossil Plants,” edited by Prof. Lebour,* there is a figure of Cyclopteris (Nephropteris) obliqua which shows two pinnules attached toa rachis; this specimen closely resembles the one I have figured, except in its much smaller size. In his earlier writings Lesquereux® retains the genus Cyclopteris, and considers that all Cyclopteroid leaves attached to stems form a distinct genus: those without stems and with arched nervures are included in Neuropteris, those without stems and with straight and diverging nervures are classed with Odontopteris. The Cyclopteroid leaves with stems are retained in the genus Cyclopteris, which is sub- divided into three sections :—(a) Adianthoides. (8) Odontopteroides. (1) Neuropteroides. In the description of fossil plants in the Report of the Geological Survey of Illinois, Lesquereux® no longer regards Cyclopteris as a distinct genus, further evidence having been obtained in favour of the connection of Neuropteris and Cyclopteris. Neuropterts is defined so as include leaflets without a median nervure. 1 Tableau des genres de végét. foss., considérés sous le point de vue de leur classi- fication botanique et de leur distribution gélogique, p. 16 (1849). 2 Fossil Flora, pl. 90 (1831-1837). 3 Fossil Flora, vol. ii. p. 28. 4 Tllust. of Fossil Plants, p. 23, pl. 11. ‘ Cae of Fossil Plants in Geology of Pennsylvania, by H. D. Rogers, vol. ll. 8). a Oa oe of Fossil Plants in Report Geol. Survey of Illinois, yol. ii. p. 427 046 A. C. Seward—Cyclopteris from the Coal-measures. In the Paleeontographica for 1868-69,' Roehl figures a large speci- men showing Neuropteris Loshit and Cyclopteris trichomanoides on the same rachis. In his description of Neuropteris Loshii he remarks :?— “On the axis or a very large frond I found Cyclopteris trichomanoides (Brongt.), which hitherto had only been found by itself, grown as axial leaves (‘Spindelblatter’) of this plant.” The Cyclopteroid leaves are in this case only attached to one side of the rachis: the size and striated character of the rachis closely connect it with my specimen. Schimper?* figures some examples under the name of Cardiopteris frondosa (Gopp.), showing large pinnules attached to a rachis: the nervation and the comparatively equilateral form of these pinnules resemble Neuropteroid rather than Cyclopteroid leaves, of which latter mine is an example. Feistmantel,* in describing the genus Cyclopteris, points out that if it is established that many of the species of Cyclopteris are basal or axial leaves (‘“ Basal—oder Spindel—blattchen”’) of Weuropteris, other species have the charac- teristics of Cyclopteris as defined by Brongniart, viz. absence of a median nervure, and the dichotomous and flabellate character of the nervures which spring from the base of the pinnules. The figures ® given by Feistmantel of Goppert’s Cyclopteris polymorpha show the pinnules attached to a rachis, but the nervures appear to start from the centre of the base as they do in Cardiopteris frondosa (Gopp.). Grand’Hury ° refers some specimens of Cyclopteris to Neuropteris, and others to Odontopteris ; he considers (4 yclopteris obliqua and C. oblata to be merely detached pinnules of Neuropteris. Mr. Kidston,’ in his catalogue of Paleeozoic plants in the British Museum, goes so far as to drop the genus Cyclopteris entirely ; he considers Cyclopteris dilatata, C. obliqua, etc., to belong to euro- pteris heterophylla and refers to Roehl’s figure in support of this view. He points out how the pinnules of Neuropteris Scheuchzeri (Hoff.) vary in form, some being the typical acute forms and others belong- ing to the Cyclopteroid type. The shape of the pinnules varies so much that it is of no specific value. In the absence of such evidence as is afforded by fructification, we must rely to a great extent on the arrangement of the nervures. In my specimen the pinnules appear to be almost opposite on the rachis, but this is of no great import- ance, as Mr. Kidston remarks,* “the alternate or opposite arrange- ment of pinne or pinnules appears to be a character of little value, as they are frequently alternate and opposite on different parts of the same frond.” Through the kindness of Prof. Lebour and Mr. Howse I was allowed to examine the Hutton collection of plants in the Newcastle Museum ; in this collection there is a specimen showing a pinnule Palezontographica, vol. xviil. taf. xvii. Ibid. p. 37: Traité de Pal. végét. pl. xxxv. (1869-74). Zeitsch. der Deutsch. Geolog. Gesell. Band xxi. p. 521. Ibid. tat. xvi. figs. 21-24. Flore Carb. du Depart. de la Loire, ete. p. 879 (1877). Catalogue of the Pal. Plants in the panes Museum, p. 90 eee) Ibid. p. 84. anraunrwnds Dr. George M. Dawson—Glaciation of British Columbia. 347 of Cyclopteris obliqua attached to a thick rachis 23 cm. in length, the pinnule is not perfectly preserved, and there are no signs of a corresponding one on the other side; the rachis is of similar appear- ance to the one in my specimen. In the present state of our knowledge it would be premature to speak positively as to the claims of Cyclopteris to be considered a distinct form, the specimen before us, however, seems to justify our retaining for the present Brongniart’s original genus. Il].—Recent OBSERVATIONS ON THE GLACIATION OF BnriTISH CoLtumBIA AND ADJACENT REGIONS. By Gzo. M. Dawson, D.Sc., F.G.S., Assistant Director, Geological Survey of Canada. es observations in British Columbia? have shown that at one stage in the Glacial period—that of maximum glaciation —a great confluent ice-mass has occupied the region which may be named the Interior Plateau, between the Coast Mountains and Gold and Rocky Mountain Ranges. From the 55th to the 49th parallel this great glacier has left traces of its general southward or south- eastward movement, which are distinct from those of subsequent local glaciers. The southern extensions or terminations of this con- fluent glacier, in Washington and Idaho Territories, have quite recently been examined by Mr. Bailley Willis and Prof. T. C. Chamberlin, of the U.S. Geological Survey. There is, further, evidence to show that this inland-ice flowed also, by transverse valleys and gaps, across the Coast Range, and that the fiords of the coast were thus deeply filled with glacier-ice which, supplemented by that originating on the Coast Range itself, buried the entire great valley which separates Vancouver Island from the mainland and discharged seaward round both ends of the island. Further north, the glacier extending from the mainland coast touched the northern shores of the Queen Charlotte Islands. The observed facts on which these general statements are based have been fully detailed in the publications already referred to, and it is not the object of this note to review former work in the region further than to enumerate the main features developed by it, and to add to these a summary of observations made during the summer of 1887 in the extreme north of British Colombia, and in the Yukon basin beyond the 60th parallel, which forms the northern boundary of that province. The littoral of the south-eastern part or “coast strip” of Alaska presents features identical with those of the previously examined coast of British Columbia, at least as far north as lat. 59°, beyond which I have not seen it. The coast archipelago has has evidently been involved in the border of a confluent glacier which spread from the mainland and was subject to minor variations 1 Quart. Journ. Geol. Soc. vol. xxxi. p. 89. did. vol. xxxiv. p. 272. Canadian Naturalist, vol. vill. * Bulletin U.S. Geol. Survey, No. 40, 1887. 348 Dr. George M. Dawson—Glaciation of British Columbia. in direction of flow dependent on surface irregularities, in the manner described in my report on the northern part of Vancouver Island.* No conclusive evidence was here found, however, either in the valley of the Stikine River or in the pass leading inland from the head of Lynn Canal, to show that the ice moved seaward across the Coast Range, though analogy with the coast to the south favours the belief that it may have done so. The front of the glacier must have passed the outer border of the Archipelago, as at Sitka, well-marked glacia- tion is found pointing toward the open Pacific? (average direction about 8. 81° W. astr.). It is, however, in the interior region, between the Coast Range and the Rocky Mountains proper and extending northward to lat. 63°, explored and examined by us in 1887, that the most interesting facts have come to light respecting the direction of movement of the Cordilleran glacier. Here, in the valleys of the Pelly and Lewes branches of the Yukon, traces were found of the movement of heavy glacier-ice in a northerly direction. Rock- surfaces thus glaciated were observed down the Pelly to the point at which it crosses the 186th meridian and on the Lewes as far north as lat. 61° 40’, the main direction in the first-named valley being north-west, in the second north-north-west. The points referred to are not, however, spoken of as limiting ones, for rock exposures suitable for the preservation of glaciation are rather infre- quent on the lower portions of both rivers and more extended examination may result in carrying evidence of the same kind much further toward the less elevated plains of the Lower Yukon. Neither the Pelly valley nor that of the Lewes is hemmed in by high mountainous country except toward the sources, and while local variations in direction of the kind previously referred to are met with, the glaciation is not susceptible of explanation by merely local agents, but rather implies the passage of a confluent or more or less connected glacier over the region. In the Lewes valley, both the sides and summits of rocky hills 300 feet above the water were found to be heavily glaciated, the direction on the summit being that of the main (north-north-west) orographic valleys, while that at lower levels in the same vicinity followed more nearly the immediate valley of the river, which here turns locally to the east of north. Glaciation was also noted in several places in the more mountainous country to the south of the Yukon basin, in the Dease and Liard valleys, but the direction of movement of the ice could not be determined satisfactorily, and the influence of local action is there less certainly eliminated. Of the glacial deposits with which the greater part of the area of the inland region is mantled, it is not intended here to give any details, though it may be mentioned that true Boulder-clay is fre- quently seen in the river-sections, and that this generally passes upward into, and is covered by, important silty beds, analogous to 1 Annual Report Geol. Surv. Canada, 1885, p. 100 B. 2 Mr. G. F. Wright has already given similar general statements with regard to this part of the Coast of Alaska, American Naturalist, March, 1887. Dr. George MU. Dawson—Glaciation of British Columbia. 3849 the silts of the Nechacco basin, further south in British Columbia, and to those of the Peace River Country to the east of the Rocky Mountains. It may be stated also that the country is generally terraced to a height of 4000 feet or more, while on an isolated mountain-top near the height of land between the Liard and Pelly rivers (Pacific-Arctic watershed) rolled gravel of varied origin was found ata height of 4800 feet, a height exceeding that of the actual watershed by over 1000 feet. Reverting to the statements made as to the direction of the general glaciation, the examination of this northern region may now be considered to have established that the main gathering-ground or névé of the great Cordilleran glacier of the west coast, was included between the 55th and 59th parallels of latitude in a region which, so far as explored, has proved to be of an exceptionally mountainous character. It would further appear that this great glacier extended, between the Coast Range and the Rocky Mountains, south-eastward nearly to lat. 48°, and north-westward to lat. 63°, or beyond, while sending also swollen streams to the Pacific Coast. In connection with the northerly direction of ice-flow here mentioned, it is interesting to recall the observations which I have collected in a recently published report of the Geological Survey, relating to the northern portion of the continent east of the Mackenzie River.’ It is there stated that for the Arctic coast of the Continent, and the Islands of the Archipelago off it, there is a con- siderable volume of evidence to show that the main direction of movement of erratics was northward. The most striking facts are those derived from Prof. 8. Haughton’s Appendix to M‘Clintock’s Voyage, where the occurrence is described of boulders and pebbles from North Somerset, at localities 100 and 185 miles north-eastward and north-westward from their supposed points of origin. Prof. Haughton also states that the east side of King-William’s Land is strewn with boulders of gneiss like that of Montreal Island, to the southward, and points out the general northward ice-movement thus indicated, referring the carriage of the boulders to floating-ice of the Glacial Period. The copper said to be picked up in large masses by the Eskimo, near Princess-Royal Island, in Prince-of-Wales Strait, as well as on Prince-of- Wales Island,? has likewise, in all probability been de- rived from the copper-bearing rocks of the Coppermine River region to the south, as this metal can scarcely be supposed to occur in place in the region of horizontal limestone where it is found. Dr. A. Armstrong, Surgeon and Naturalist to the “Investigator,” notes the occurrence of granitic and other crystalline rocks not only on the south shore of Baring Land, but also on the hills at some distance from the shore. These, from what is now known of the region, must be supposed to have come from the continental land to the southward. 1 Notes to accompany a Map of the Northern Portion of the Dominion of Canada, East of the Rocky Mountains, p. 57 R., Annual Report, 1886. * De Rance, in Nature, vol. xi. p. 492. 350 = R. Lydekker—Oxford and Kimeridge Clay Sauropterygia. Dr. Bessels, again, remarks on the abundance of boulders on the shore of Smith’s Sound in lat. 81° 30’, which are manifestly derived from known localities on the Greenland coast much further southward, and adds, ‘‘ Drawing a conclusion from such observations, it becomes evident that the main line of the drift, indicating the direction of its motion, runs from south to north.” ? It may further be mentioned that Dr. R. Bell, of the Canadian Geological Survey, has found evidence of a northward or north-east- ward movement of glacier-ice in the northern part of Hudson Bay, with distinct indications of eastward glaciation in Hudson Strait.? For the Northern part of the Great Mackenzie Valley we are as yet without any very definite information, but Sir J. Richardson notes that Laurentian boulders are scattered westward over the nearly horizontal limestones of the district. Taken in conjunction with the facts for the more southern portion of the Continent, already pretty well known, the observations here outlined would appear to indicate a general movement of ice outward, in all directions, from the great Laurentian axis or plateau which extends from Labrador round the southern extremity of Hudson Bay to the Arctic Sea; while a second, smaller, though still very important region of dispersion—the Cordilleran glacier-mass—occupied the Rocky Mountain region on the west, with the northern and southern limits before approximately stated. I have refrained from entering into any detail at this time in respect to the glaciation of the northern part of the Cordillera belt, as it is probable that within the year we shall be more fully informed on the subject, as the result of observations to be expected from Mr. R. G. M‘Connell of this Survey. Mr. M‘Connell is now on the Mackenzie River, which, as well as the Porcupine branch of the Yukon, within the Arctic circle, it is intended that he shall examine during the summer. ITV.—NOoreES ON THE SAUROPTERYGIA OF THE OxForD AND KIMERIDGE CLAYS, MAINLY BASED ON THE CoLLeEcTION oF Mr. Lreps at Eyr- BURY. By R. Lyprxxer, B.A., F.G.S8., ete. PRESUME that most English students of Mesozoic Reptiles are acquainted, at least by report, with the magnificent collection of the remains of Sauropterygians and other Saurians from the Oxford Clay of Northamptonshire in the possession of Mr. A. N. Leeds, of Eyebury, near Peterborough. Those, however, who have not had the good fortune to see this unrivalled collection, can have no idea of its richness, or of the light it throws on the crganization and affinities of the Sauropterygians of the later Jurassic seas. Tull a few weeks ago I was among the number of those to whom this collection was known merely by report: but at the end of June I availed myself of Mr. Leeds’ courteous invitation to see and study his 1 Nature, vol. ix. 2 Annual Report Geol. Surv. Canada, 1885, p. 14 D.D.; and Report of Progress, 1882-84, p. 86 D.D. R. Lydekker—Oxford and Kimeridge Clay Sauropterygia. 351 collection as fully as I might desire. On arrival, my astonishment was unfeigned to find that this collection comprised not, as I expected, only one or two imperfect skeletons of one or more species, but in some cases as many as five or six almost entire skeletons belonging to as many individuals of four well-defined species. The specimens are arranged on shelves and in trays in two rather small rooms, which they almost completely fill; and so perfect are many of them that there would be no great difficulty in mounting entire skeletons of these extinct Saurians in the same manner as those of existing Cetaceans are exhibited in our Museums. In many cases every process and spine of the vertebrze is absolutely perfect, owing to the. careful and patient manner in which Mr. Leeds has personally extracted the skeletons from the soft clay in which they lay embedded. The paddles too, which have been such a stumbling-block to the paleontologist, have every bone in its natural position, so that there can no longer be any doubt as to their mode of arrangement. Apart, however, from the intrinsic perfection of this collection, its great importance consists in the clearing up of the relations and affinities of the many so-called species of Sauropterygians which have been described upon more or less imperfect remains from the Oxford Clay. In order to avail myself of the full advantages to be gathered from a visit to this collection, I had carefully studied all the specimens previously described from this horizon ; and, through the courtesy of Prof. A. H. Green, I had the further advantage of having the type vertebrae on which the late Professor Phillips founded his Plesiosaurus Oxoniensis and P. plicatus at the British Museum. Fic, 1.— Posterior (1), hemal (2), and anterior (3) aspects of a cervical vertebra of Plesiosaurus plicatus, from the Oxford Clay, 5. (After Phillips.) The first skeleton to which I directed my attention was the some- what imperfect one which Prof. H. G. Seeley described some years ago in vol. xxx. of the Geological Society’s Journal, under the new generic and specific name of Murenosaurus Leedsi. Since that specimen was found Mr. Leeds has obtained several other much less imperfect skeletons of both immature and adult individuals, which he refers, and in my judgment quite correctly, to the same species. The immature skeletons show, however, that the cervical vertebra are quite indistinguishable from those from the Oxford Clay near Oxford, to which Prof. Phillips applied the name P. plicatus (Fig. 1) ; and the specificname Leedsi must, therefore, yield place to this earlier one. The most important point, however, on which these new skeletons throw 3852 Rk. Lydekker—Oxford and Kimeridge Clay Sauropterygia. light is the structure of the pectoral girdle. It will be remembered that the genus Murenosaurus was founded upon a supposed peculiarity of this part of the skeleton—to wit, that the preaxial border of the coracoids was not connected by a median bony bar with the pre- coracoids (using the terms employed by Mr. J. W. Hulke). Now the new specimens show that this restoration of the pectoral girdle is solely due to the imperfection of the type specimen; and, as Mr. Leeds at once pointed out to me, the portion of the scapulo-precora- coid regarded as the precoracoid in the figure given in the Q J.G.8. vol. xxx. p. 448, and made to meet its fellow in the middle line, is really the dorsal part of the scapula. The pectoral girdle is in fact of the same general structure as that figured by Prof. Seeley on p. 447 of the same volume as the type of the so-called Colymbosaurus ; and there appears to be no distinction, so far as regards the pectoral girdle (on which the two were founded), of both Murenosaurus and Colymbosaurus from the earlier EHlasmosaurus of Prof. Cope. If, however, we follow Mr. Hulke in retaining the Jurassic and Cretaceous Sauropterygians exhibiting this modification of the pectoral girdle in the original genus. Plesiosaurus, of which they form a well-marked group, then we may continue to use the name Plesiosaurus plicatus for this species. An allied, and apparently unnamed species, represented in Mr. Leeds’ collection, and dis- tinguished by its shorter cervical vertebra, which are also fewer in number, is also known to me by a considerable portion of a skeleton obtained from the Oxford Clay of Weymouth. This form I shall describe, and if necessary name on a future occasion; Mr. Leeds having kindly lent me one.of the cervicals of his mature example. The next species I have to mention is P. Oxoniensis, represented by several nearly entire skeletons in the Eyebury Colléction. Of the specific identity of these examples I have satisfied myself by a com- parison with the type cervical and dorsal vertebra in the Oxford Museum. ‘This species was referred by Prof. Seeley to a subgenus of Murenosaurus—I presume on the evidence of a pectoral girdle figured in Phillips’s “Geology of Oxford” (p. 810), which is turned the wrong way upward and described as the pelvis. The coracoids (pubes) in that example are, however, I believe, referable to the so-called Plesiosaurus philarchus; and the Eyebury specimens show that the pectoral girdle was of the type of the so-called Colymbo- saurus. These specimens show, moreover, that the remarkable pectoral limb from the Oxford Clay of Bedford, figured by Phillips on p. 815 as a pelvic limb, and made the type of P. eurymerus, is really referable to P. Oxoniensis ; the limb figured on p. 312 of the “Geology of Oxford” under the latter name apparently belonging to P. plicatus. A fourth species represented in Mr. Leeds’ collection is the so- called Plesiosaurus philarchus of Prof. Seeley, characterized by its long mandibular symphysis. The examples of this species show that in the young there were two distinct costal facets in the cervical vertebre ; while the teeth, and pectoral and pelvic girdles, present a great resemblance to those of Pliosaurus. This species seems to R. Lydekker—Oxford and Kimeridge Clay Sauropterygia. 3538 be closely allied to Thawmatosaurus oolithicus, of the Lower Jurassic of Wiirtemberg, in which the teeth have the same structure and the cervical vertebree are likewise furnished with two costal facets. The latter species, again, appears to come so close to the Upper Liassic Plesiosaurus Cramptoni—the type of Prof. Seeley’s genus Rhomaleo- saurus—-that with our present material not even specific characters can be recognized. On these grounds I am inclined to include all these three species, together with the Lower Liassic P. megacephalus, in a single genus, for which the name Thaumatosaurus should be adopted. This reference J shall again have occasion to mention in an addendum to a paper on the Oxfordian species in the ‘“ Geological Society’s Journal”; the knowledge J have gained since that paper was read having induced me to remove that species from the genus Plesiosaurus. Mr. Leeds’ examples show that a small omosternum was present. Of the genus Pliosaurus Mr. Leeds possesses only a number of detached teeth, which differ from those of the Kimeridgian forms in the imperfect development of the “carine,” and the absence of the distinct smooth and flat intercarinal space. These teeth appear indistinguishable from the one from the Oxfordian of Boulogne described and figured by M. Sauvage under the name of Liopleurodon feroz. I can see, however, no reason why this species should be separated from the Owenian genus, and it may accordingly be known as Pliosaurus ferow. 'The cervical vertebrae from the Oxford Clay in the Cambridge Museum to which Prof. Seeley has applied the name P. pachydirus, without, however, giving any specific diagnosis, are probably referable to the same species. Leaving now the Eyebury Collection with the expression of my thanks to its owner for his courtesy in placing it thus freely before me, our attention may be directed in the remaining part of this paper to certain large Plesiosaurian remains from the Kimeridge Clay, which are allied to P. Oxoniensis. In the first place I may mention that after leaving Peterborough I availed myself of the permission of Mr. Marshall Fisher, of Ely, to visit his collection, which contains the pectoral girdle figured by Prof. Seeley on p. 447 of the thirtieth volume of the “ Geological Society’s Journal,” under the name of Colymbosaurus, and thence proceeded to the Woodwardian Museum at Cambridge to have one more look at the vertebral column to which the same authority has given the name of Plesiosaurus megadirus ; both specimens being from the Kimeridge Clay of the Cambridge- shire district. Before going further it is, however, necessary to recapitulate briefly the history of these large Kimeridgian Plesiosaurs. In the “ British Association Report ” for 1839, Sir R. Owen described a propodial bone (humerus or femur) of a large Plesiosaur from the Kimeridge Clay of Shotover in the collection of the late Lord Enniskillen, under the name of Plesiosaurus trochanterius ; this specimen being now in the British Museum. Its structure is shown in the accompanying woodcut of anotherexample. In the year 1841 this species, together with P. grandis, was referred to the genus Pliosaurus; of which the DECADE III.—VOL. V.—NO. VIII. 23 304 R. Lydekker—Oxford and Kimeridge Clay Sauropterygia. type is P. brachydirus, described in the previous year in the same writer’s ‘“Odontography.” In 1869 Prof. Seeley, in his “‘ Index to the Woodwardian Museum,” applied the name Plesiosaurus megadirus to the above-mentioned vertebral column in the Cambridge Museum ; merely, however, mentioning its large size and the number of the cervical vertebra, and the description being therefore insufficient to authenticate the name. A second imperfect skeleton, in the same collection (presented by Mr. Stead Jones), was referred to the same species; that specimen having a propodial of the peculiar type of P. trochanterius. In the following year Mr. Hulke described in the Q.J.G.S. vol. xxvi. the vertebral column, the pectoral and pelvic pro- podials, and the imperfect coracoids of a large Plesiosaur from the Kimeridge Clay of Dorsetshire under the name of P. Manseli; and also certain dorsal vertebree remarkable for their very short centra, to which the name P. brachistospondylus was accordingly applied. In the course of the description of the former species the resemblance of the propodials to the type of P. trochanterius was pointed out, and no very good reasons were given why the specimen should not have been referred to that species, which was thus proved to be Plesio- saurian. Gili . ft i ay \ Qa = Fie. 2.—Dorsal aspect of the right humerus of Plestosaurus trochanterius ; from the Kimeridge Claveto sama. preaxial, p, postaxial border ; e, division between radial and ulnar facets. (After Phillips.) Reference was also made to P. megadirus, which was considered to be closely allied, although it was stated that in the opinion of Mr. W. Davies it was not identical. It should be added that Mr. Hulke’s types are preserved in the British Museum. The year 1871 saw the publication of Phillips’s “Geology of Oxford,” in which work vertebra of large Plesiosaurs from the Kimeridgian of Oxfordshire were described under the names of P. brachyspondylus and P. validus ; the former being wrongly identified with P. brachyspondylus of Owen, which is really a Pliosaur, and the latter being regarded as new. No reference (perhaps owing to the close sequence of the two works) was, however, made to Mr. Hulke’ s P. Manseli; and detached R. Lydekker—Oxford and Kimeridge Clay Sauropterygia. 355 propodials were described under the name of P. trochanterius. P. brachyspondylus was regarded as the Kimeridgian analogue of P. Oxoniensis ; the vertebre having the same short and distinctly cupped centra, which characterize both that species and P. Mansel. It should also be observed that Phillips described another large Kimeridgian Plesiosaur, which had flattened terminal faces to the centra, and is closely allied to P. plicatus, which belongs to a totally different sub- group. ‘Thus matters stood till 1874, when in vol. xxx. of the Q.J.G.S., Professor Seeley figured on p. 447 the above-mentioned pectoral girdle from Ely, under the new generic title of Colymbo- saurus ; stating on p. 445 that the type species was to be P. megadirus, which, as already stated, had never been sufficiently described. It was also mentioned on p. 448 that Plesiosaurus Manseli was to be referred to a subgenus of Murenosaurus. With these facts we may proceed to criticism. In the first place I cannot find any characters by which P. Manseli can be distinguished from P. trochanterius, and since the description of the latter is suffi- cient, I consider that we should adopt the earlier name. P. brachisto- spondylus appears, moreover, to be founded upon dorsal vertebrze of the same species which have been subjected to a strong crush in the axial direction. I have compared the vertebre figured by Phillips under the name of P. brachyspondylus, and also the types of his P. validus, with the corresponding vertebra of the column described by Mr. Hulke, and find an absolute identity between the two; the difference on which Phillips separated P. validus from P. brachyspon- dylus being merely due to the different serial position of the vertebre, and to an erroneous restoration of the neural arch. With regard to the type skeleton of P. megadirus, Prof. Hughes has been good enough to send some of the cervical vertebrae to London, and from coim- paring these, and from a personal examination of the rest of the skeleton two days after having carefully examined that of the so- called P. Manseli, I am fully and absolutely convinced of the specific identity of the two. This is also borne out by all the detached vertebre of this type from the Cambridgeshire district in the British Museum, which cannot be distinguished from those of the latter. Further evidence is afforded by the above-mentioned paddle in the Cambridge Museum, and by another in the collection of Mr. Fisher, in both of which the propodial is of the P. trochanterius type. Now comes the question of the pectoral girdle on which Colymbo- saurus was founded. As this was referred definitely by its describer to the so-called P. megadirus, 1 had imagined that it was associated with vertebree of the same type as those of the latter; but my astonishment on arriving at Ely was considerable on hearing from Mr. Fisher that it was an entirely isolated specimen. Although I think it most probable that this specimen is referable to the present form—that is, P. trochanterius—yet Prof. Seeley, on the supposition that these two forms were distinct, had no more grounds for referring it to P. megadirus rather than to P. Manseli, unless he assumed that all the Cambridgeshire specimens belonged to the former and all the Dorsetshire to the latter. Even then, however, there was also the 306 W. W. Watts—On Outerops. possibility of this specimen belonging to the large form allied to P. plicatus (for which I propose to adopt Owen’s name P. truncatus), of which there are vertebrae from Ely in the British Museum. So far, therefore, as I can see, the forms described under the names of P. trochanterius, P. megadirus, P. brachistospondylus, P. Manseli, P. brachyspondylus (Phillips), and P. validus, belong to one and the same species. On the evidence of a detached pectoral girdle Prof. Seeley has, however, made P. megadirus the type of the genus Colymbosaurus, while P. Manseli is referred to a second genus, Murenosaurus, apparently on the evidence of the broken coracoids of the type specimen. I think it very probable, as already said, that the pectoral girdle in question does belong to the present species ; and I believe, moreover, that the pectoral girdle of the type specimen of P. Manseli when complete was (as Mr. Hulke states on p. 59 of the “ Proc. Geol. Soc.” for 1883) of precisely the same general form ; this form having apparently obtained in all the Upper and Middle Jurassic Plesiosaurs. As a climax to the treatment to which Plesiosaurs have been subjected we may notice Prof. Cope’s restoration of the so-called Hlasmosaurus platyurus, given in the ‘Trans. Amer. Phil. Soc.” vol. xiv. pt. i. pl. ii. In this instance the head has been placed at the extremity of the tail; and the Professor is consequently led to remark in his description that in the vertebra the prezygapophyses present the unheard-of peculiarity of looking downwards instead of upwards, while the so-called cervicals are indistinguishable from the caudals of other forms. Finally, after long consideration I have come to the conclusion that it will be convenient to separate from Plesiosaurus all those supra-Liassic species having single costal facets and a pectoral girdle without omosternum and the coracoids united by a median bar with the precoracoids. For these forms I propose to adopt the name Cimoliosaurus, Leidy, as being the earliest of the numerous terms which have been applied to this group. The typical forms have flattened terminal faces to the vertebree; but I do not propose to generically separate these forms like Plesiosaurus trochanterius and P. Oxoniensis in which these faces are cupped; although if such separation should be found advisable, I believe the term Polycotylus of Cope is the one which should be adopted. I shall show on another occasion that Hlasmosaurus of Cope is not separable from Cimoliosaurus. V.—Ovrtorops. By W. W. Warts, M.A., F.G.S., Fellow of Sidney College, Cambridge, and sometime Deputy-Professor of Geology at Oxford. OW that mapping constitutes such an essential part of field-work, it may be of use to some of your readers to connect together a few rules which have occurred to me on this subject. Valley-Outerops.—Professor Green has devised an admirably com- mon sense method by which the outcrop of a flat rock-bed can be W. W. Watts—On Outcrops. 307 traced by means of contour lines. The main results gained from this method may be thus summed up :— 1. A bed of rock parallel with the waterway of a valley crops out in two parallel lines. If the plane be turned through 180°, the lines begin to meet (a) down the valley where the inclination is in the same direction as, and greater than, that of the waterway ; in every other case (b), they meet up the valley. 2. Where the strike crosses the waterway obliquely, the sharpest change in the outcrop line will be on that side of the valley where the acute angle made by the strike with the contour lines is smallest in case (a), and greatest in case (0). Fic. 1. Fie. 2. Fre. 1. Outcrop in valley; strike oblique ; dip with waterway. Fie. 2. Ditto $5 3 ; dip against waterway. Strike-faults.—Sometimes one is apt to think that the whole nomenclature of faults is unsatisfactory, and some of the terms used, hade particularly, misleading. But a little careful consideration will convince us that it is quite right to refer the inclination of hade to a vertical plane and not to one at right angles to the strata; for the two forces responsible for the results of faults are gravitation and crust-crushing, and these two forces together determine the direction of movement. After drawing all the possible cases of strike fault- ing it is clear that all normal faults, as ordinarily defined, are due to movement under the influence of gravitation where rocks have been stretched and cracked, and have moved so as to gain space. Reversed faults, on the other hand, are those in which compression has occurred and space has been saved. The result is that all normal faults, with one exceptional type, tend to repeat the outcrop of beds, while reversed faults, with a parallel exception, have a tendency to conceal beds. As the excep- tions belong to types of frequent occurrence, Figs. 3 and 4 illus- 358 G. W. Colenutt—On the Osborne Beds. trate them, and it will be observed that in both cases the hade of the fault is in the same direction as the dip, but at a greater angle than it. To contrast with these figures I have chosen two other faults for Figs. 5 and 6, each belonging to one of the other two types. Fia. 3. Fia. 4. Fie. 3.—Normal fault, concealing bed 5. Fic. 4.—Reversed fault repeating beds 3—4. Fic. 5.—Normal fault repeating beds 0—1. Fic. 6.—Reversed fault, concealing bed 4. Additional complexities will of course be introduced if faults have a hade lower than the angle of ground slope; but I prefer to leave each such case to be dealt with on its own merits. Dip-faults—The result of a number of drawings of faults shows that the following law exists. The outcrop on the upthrow side is pushed forward in the direction of dip, unless the angle of the latter is less than that of the ground slope, when the reverse occurs. Good figures will be found in the manuals by Professors Green and J. Geikie. Connecting together the exceptions in all these cases, we find they occur—when the strata dip at (1) a less angle than (a) the ground in a dip fault, (b) the hade in a strike fault, and (2) at a greater ASIC than the ground in the valley outcrop. VI.—On a Portion oF THE OsBoRNE BEDS OF THE IsLE OF WIGHT, AND ON SOME REMARKABLE ORGANIC REMAINS RECENTLY DIS- COVERED THEREIN. By G. W. Cotenvurt, Esa. T several places along the north-eastern coast of the Isle of Wight the Osborne Beds crop out on the shore to some extent and admit of examination. From the great difficulty which is usually experienced by geologists in getting at any workable section or outcrop of these beds but little, one might say almost nothing, is known about them. ‘There are few divisions of the Tertiary strata of the Island which present so many variations both of composition G. W. Colenutt—On the Osborne Beds. 309 and of fossil contents as do the Osborne Beds at their various out- crops; and at the three places where they are most usually examined —at Whitecliff Bay, at St. Helen’s, and at Alum Bay—they yield few fossils, and there is nothing extraordinary about the composition of the clayey strata. On the contrary, at several places between St. Helen’s and Osborne these beds crop out from underneath the overlying Bembridge Limestone at places which might easily be overlooked, and present very remarkable features both as to their composition and as to the fossils which they contain. Some descrip- tion of these strata, and of the organic remains contained in them, may be of interest, as so little is known of them; and the more so as it has been my good fortune to discover in some of the clays organic remains which there is reason to believe are quite new, if not to science, at least to our English strata. The Osborne Beds in the Hast Medina may be examined on the shore at several places, more especially below Chapelcorner Copse, between King’s Quay and Wootton Creek: just to the west of the boathouse on the shore below Binstead House: on the shore below Ryde House: and immediately to the south-east of Sea View Pier. At all these places the most interesting clays are exposed not in the cliff, but on the beach itself; consequently the strata are not very often seen, being usually covered up and hidden by the shingle and sand of the beach, and more especially so at the last three of the above- named places. At Chapelcorner Copse, on the contrary, the section is generally fairly well exposed, as there is comparatively but little shingle and sand to the west of Wootton Creek; and, as they are practically identical, it will be well to take the strata here as repre- sentative of those at the other localities. It is very difficult to get exact measurements on account of the cliff for some distance inland being covered by a sliding talus of grey and yellow clays thickly covered with underwood. The Bembridge Limestone will, however, be observed in the top part of the cliff and under this we find the following approximate section :— (In the cliff.) Ft. 1. Marls and yellow-grey and dark red and mottled clays ... ... .. ... about 40 (On the beach.) 2. Grey clay with scattered fish bones, scales, etc. .. NCCC HPN Nice 3. Hard blue and grey shaly clay with small perfect fossil fish . , sah ee 4. Hard grey clay with matted masses of leaves and lenticular masses of * _cement-stone ... . SS. 5. Blue clay with many seams of crushed Paludina lenta and Melanopsis carinata .. ecules AN 6 6, Unfossiliferous soft green clays extending to low-water mark. The clays numbered 2, 3, 4, and 5 in the above section are the most important, and afford valuable information as to the flora and fauna which flourished when they were deposited. In number 2 thin lenticular masses of crushed fish bones occur, with many ganoid scales and fish vertebra (Lepidosteus): teeth, bones, and dermal plates of Alligator Hantoniensis (?): bones and plates of Hmys, Trionyx, and Chelone: incisor and molar teeth and 360 G. W. Colenutt—On the Osborne Beds. bones of a small rodent (Theridomys) [rare]: a small snake vertebra was found among the crushed bones and also a jaw of Lepidosteus (2). In number 3 the most remarkable fossils are found in a hard, dark grey laminated clay, and consist of small exquisitely perfect teleostean fish, varying in length from three-quarters of an inch to three inches : also bones, scales, and vertebre of larger fish: crustaceans apparently allied to the shrimp or prawn and measuring from half an inch to two and a half inches in length [rare]: Cyprides: occasional masses of crushed Paludina lenta and Melanopsis carinata: a few scattered ganoid scales : and spines and bones of larger fish. In number 4 seams of compressed vegetable remains occur: a few leaflets of ferns [rare]: small carbonized seed vessels, with longitu- dinal striations (not yet identified) : a few small twigs of a Conifer : occasional masses of lignite: and detached fragments of turtle plates. In number 5 Paludina lenta and Melanopsis carinata occur abundantly in thin seams, but they are mostly in a crushed state. No other species of Mollusca have been observed. Vertebrze of large fish occur, especially in a thin seam of finely comminuted shells at the base of this division: teeth apparently of Alligator Hantoniensis are found in this division, but they are rare here; a few detached turtle plates are found, but they are not so ues met with here as in the clay a little higher up. In number 6 and in number 1 I have not been able to discover the existence of any organic remains at all. The strata have a very slight dip of about 5° or 6° to the south ; but this dip, close to the base of the cliff, is much increased—caused no doubt by the weight of the talus, which in wet weather is in a very soft and oozy state, and is always on the move down towards the shore. The beds above described occupy about the middle of the Osborne series, but the dark clay in which the small perfect fish occur is no doubt a local deposit, although it occurs at Binstead House, Ryde House, and at Sea View, as well as at Chapelcorner Copse. The distance is about 5} miles, as the crow flies, between the furthest outcrop of the fish clay to the west (at Chapelcorner Copse), and the furthest outcrop to the east (on the shore in the angle formed by the sea-wall immediately to the south-east of Sea View pier). Thus it will be seen that the deposit is of considerable extent, although it is no doubt correctly considered as local. Although I have at every opportunity made a most careful search, I have never been able to discover the presence of this clay at any of the other places in the island where the Osborne Beds are ex- posed. At Whitecliff Bay, where the Osborne Series is visible in its entirety, I have been unable to find any trace of the fish clay ; neither have I at Gurnard Bay, nor at any of the other sections in the West Medina. The shore sections between Ryde and Sea View are much obscured by the sea-wall which runs the entire distance, thus preventing any examination of the clays which would crop out along the beach and low cliffs. The small fossil fish from division 3 are most beautifully pre- G. W. Colenutt—On the Osborne Beds. 361 served—even the minute rays of the fins and tails being most clearly defined. From the fact that the fish are largely impregnated with iron pyrites, they present a beautiful golden appearance, especially when first exhumed from the clay. The head is not, as a rule, so well defined as the other portions of the body, yet it is very often possible to see the eye preserved as a black spot, and the discoloura- tion of the intestines is sometimes seen in the specimens. It is not usual to meet with one fish alone, but they generally occur in small shoals—the remains of no less than nine separate and distinct fish being imbedded in a small slab of clay measuring two and a quarter inches square, which I have in my cabinet. This, however, is an exceptionally good shoal. A good deal of iron pyrites occurs in the clay in small soft, gritty, dark-grey masses, and some of the larger specimens of the fish are much disfigured and spoilt by the iron pyrites with which they are encrusted, and into which they are transformed. In several other divisions of the clay we find iron pyrites matting the shells together into thin slabs, and occurring as irregular brown masses in the clays. It is always very interesting to endeavour to ascertain from the -evidences presented, the origin and mode of formation of a local or accidental deposit like the fish clay, and to arrive approximately at some idea of the state of things both before and after the occurrence happened which gave rise to the deposit. In the clays underneath the fish clay we find evidences of the existence of a comparatively tranquil lake or river inhabited by Puludina, Melanopsis, Cypris, Trionyx, and other similar forms. The flora is represented by crushed masses of vegetable remains and by plants of which we find the seeds (not yet identified). A few ferns existed on the land, but the remains of these are very rare. as also are the few remains of conifers. That the area of deposit was but little disturbed is evident from the perfect condition in which the vegetable remains are preserved, for they show no signs at all of having been subjected to attrition. But a change took place in the form of a sudden influx of mud and foreign matter. It remains to be seen from careful and expert examination whether the fish which we find in this clay may be assigned to any genus of fish inhabiting the sea, or whether they are clearly of freshwater origin ; and very considerable interest attaches to the solution of this question. That the fish were smothered by the mud is perfectly clear, for the result even of a day’s decay would be to damage and spoil the delicate bones of the fins and tails. Then again, these fish are found entombed in a perfect state in small shoals, which would not be the case had they died a natural death and been drifted together—they would be more or less damaged by the drifting process. And I have never found vegetable or any other remains mixed up with the fish— which one would expect to do in the case of drifted exuvie. In several cases the fish have been compressed flat without being laid on their sides, and in these cases we see the fish from above and do not see the dorsal fin at all, but both eyes are visible in the form of two black spots, one on either side of the head. Masses of commi- 362 Dr. Chas. A. White—On a New Cretaceous Coral. nuted bones of larger fish do occur, but not on the exact horizon occupied by the small perfect fish—they are either just above or just below. The shrimps or prawns, which are found on precisely the same horizon as the perfect fish, are too in a very perfect state, and this is another fact in support of death by smothering. It seems doubtful whether such crustaceans as these—the largest I have measures about two and a half inches in length—were inhabitants of freshwater, but rather were drifted into the river or lake from the sea with the mud (and possibly with the small fish) and there entombed alive. Again, the texture of this fish clay is quite different from anything above or below it—indeed it is quite different from any of the Tertiary clay of the Island—being shaly and readily splitting into layers. It has also a well-defined transverse jointing, and this property is the cause of its easily dividing into irregular masses, in which state it is often rolled about by the waves and water-worn into rounded nodules. There is one very thin seam of Paludina and Melanopsis forming the top layer of the fish clay, as though after the fish clay had been deposited, the freshwater inhabi- tants had all been killed also by the influx of salt water or other agency; in the clay above no remains of mollusca are found at all. The whole scheme of life seems to have changed and the only organic remains are those of large fish and reptiles with the bones of a few small mammals. Above the horizon of these seams of fish bones we find nothing but grey and yellowish and red mottled unfossiliferous clays of varying hardness, which seem to point to water—probably of a brackish nature—but with an almost total absence of the usual _ freshwater life. Above these beds of clay comes the Bembridge Limestone showing the reverting to purely freshwater conditions, and the consequent recurrence of a freshwater fauna. The small fish and the shrimps were first discovered in the year 1876, at Ryde House, and since that time I have, from the several localities, obtained about one hundred and fifty specimens of the former and about twelve specimens of the latter. [N.B.—Mr. E. T. Newton, F.G.8., of the Museum of Geology, Jermyn Street, is examining and naming the fish and Crustaceans mentioned in this paper, and his description of them will appear» in due course. | VIL—On Hinvrastrz4, 4 New Generic Form or Creracrous ASTREIDE. By Dr. Cuartes A. Wuire. Palontologist, U.S. Geological Survey. VHE little Coral here described was discovered in Kaufman County, Texas, in strata of the Ripley Group, by Dr. R. H. Loughridge, and presented by him to me, together with a few characteristic molluscan species of that group which he found asso- ciated with it. The Ripley Group is the uppermost division of the Cretaceous series in the States which border upon the Gulf of Dr. Chas. A. White—On a New Cretaceous Coral. 8568 Mexico; and probably represents approximately the Upper Chalk of England. Regarding it as a new generic form I herewith give a diagnosis and figures of it; and being the only species known to me, the diagnosis is necessarily based upon this alone. HINDEASTR#A, gen. nov. Corallum depressed or discoid, simple in the earlier stages of growth, but afterward becoming compound by gemmation ; basal epitheca marked by both radiating striae and concentric rugz : corallites few, without true columella, their outer walls fused together when in contact, and moderately strong; radiating septa bilaminate, subequal in thickness at their peripheral ends, consisting of three or four cycles as regards their length, subspinulose, tuber- culose, or rugose upon their sides and upon their free upper edges ; dissepiments few or absent. Fig. Fig. Fig. Calicular view of the largest example discovered. Lateral view of the same. . Calicular view of a medium sized example. Fig. 4. Under view of the same, showing the basal epitheca. Fig. 5. Calicular view of a corallite upon which no gemmation has occurred. All the figures are of natural size. This genus is related to Isasirea, HE. and H., but it differs from the latter in its mode of growth, Isastrea being massive, and the dissepiments of its corallites being usually numerous and well developed. The extreme shortness of the axis of the corallites of Hindeastrea gives little or no space for the development of dissepi- ments. The walls of the corallites also form more distinct boundaries between the calices than is usual in Isastrea. The generic name is given in honour of Dr. G. Jennings Hinde. on He 09 29 FS HINDEASTR#A DISCOIDEA, Sp. NOV. Corallum irregularly discoid or much depressed, attached by the apex of the original corallite, or free; corallites few, very short but moderately broad; the walls of the adjacent corallites usually in contact and fused together, when the border is polygonal ; but they sometimes have a tendency to separate, when the border is sub- circular; calices slightly concave or nearly flat; their borders more or less prominent and clearly defined; radiating septa prominent, 364 Notices of Memoirs— Dollo and Storms—Fossil Fishes. 22 to 26, usually 24, in number; those of the first cycle four to six in number, reaching nearly or quite to the centre of the corallite, where they are more or less contorted. Those of the second cycle do not usually terminate interiorly by free ends, but are there joined to one another or to those of the first cycle. Those of the third cycle usually terminate like those of the second, but are sometimes free at the inner end; the sides and free edges of the septa subspinulose or tuberculose. The number of corallites in a corallum varies from one to seven or eight, their gemmation taking place at the margin of the calice, and usually after the original corallite had attained considerable size. Diameter of the largest calice observed, 8 millimeters. The type specimens! are preserved in the U. S. National Museum, at Washington. WASHINGTON, June 12th, 1888. NOTICES OF MEMOTRS. J.—“ Scr tes TéLfostiens pu Rupfiiren.” By L. Dotto and R. Storms. (Zool. Anzeiger, No. 279, 1888.) \ ESSRS. DOLLO and STORMS have undertaken the investiga- i tion of the Fossil Fishes of the Mesozoic and Tertiary deposits of Belgium, and we are glad to welcome the first brief instalment of the results of their joint researches. The present note deals with the systematic position and nomenclature of the genera Sphyrenodus, Agassiz, and Scomberodon, P. J. van Beneden. Dictyodus, Owen, is adopted as the correct name for the so-called Sphyrenodus, and the fish is referred to the Scombride, on account of the characters of its dentition, premaxilla, palatine, mandible, and the caudal region of the vertebra] column. It is respectively separated from Cybium and Pelamys, its nearest allies, by its single series of large conical palatine teeth, and by the greater strength of its dentition and pre- inaxilla. Scomberodon is considered to be identical with Cybium, and the type must henceforth be known as Cybium Dumonti. A. S. W. II.—Pror. Dr. W. Dames on GiganTicuTHYys PHARAO, (Sitzungsb. : Ges. naturf. Freunde Berlin, 1887, p. 187.) NHE generic name Titanichthys being preoccupied, Prof. Dames suggests that of Gigantichthys for the large Cretaceous fish- teeth from Egypt, already described under the name of Titanichthys pharao (see Grou. Mag. for April, 1888, p. 157). 1 Specimens of this Coral have been presented to the British Natural History Museum through Dr. G. J. Hinde. Reviews— J. J. Harris Teall’s Petrography. 369 See ae Ve Ses VV SS I.—British PETROGRAPHY, WITH SPECIAL REFERENCE TO THE Ienzous Rocks. By J.J. Harris Tear, M.A., F.G.S. (London, Dulau & Co., 1888.) Royal octavo, pp. 470, with 47 Chromo- lithographic Plates. OR some years students have been longing for a well-illustrated and comprehensive work on the mineral structure of rocks. Memoirs on certain parts of the subject, such as Wadsworth’s Lithological Studies, or Zirkel’s Microscopical Petrography, were accessible without much difficulty ; there was the Minéralogie Micro- graphique of MM. Fouqueé and Lévy, with its splendid illustrations, but this is written too much from the mineralogical point of view for the ordinary student, and Professor Rosenbusch’s ‘‘ Mikroscopische Physiographie der massigen Gesteine,” though a treasure house of erudition, is vitiated by a faulty principle of classification, and is almost without illustrations. Moreover, it is not every student who can read French or German with as much facility as English. We have now a book in our own language which is comparable in its illustrations with that of Fouqué and Lévy, and in its erudition with the treatise of Rosenbusch. True, it deals only with British rocks, but these are so comprehensive, that there is comparatively little wanting to make it a complete work of reference so far as those of igneous origin are concerned. The work is illustrated by several woodcuts interspersed in the text and by 47 coloured plates—the former occasionally leave some- thing to be desired in clearness, but the latter as a rule are excellent, and are accompanied by outline key-plates. The examples on the whole appear to be very judiciously selected. The task before Mr. Teall was not quite so difficult as the proverbial decanting the Ocean into a pint pot; but still the plethora of wealth must have caused him no little embarrassment. If we were disposed to take exceptions, we should say that a little too much favour had been shown to the more basic rocks, though in these we still desiderate a tachylite, and to the pyroxenic group of minerals, and that the selection of the non-igneous rocks, necessarily a very restricted one, was not in every case the best possible. Of the 47 plates, rather more than eight are devoted to the peridotites, picrites, and serpen- tines, and it takes full thirty plates to get clear of the more basic half of the igneous rocks. Thus, the more acid group—granites, quartziferous felstones, pitchstones, and kindred rocks—seem to us rather inadequately represented. It is, no doubt, difficult among so many excellent figures to suggest excision, but we doubt whether two are needed in the case of quartzite, and whether the student will learn much from that of a crushed quartzite. Indeed, either the figure is not very successful, or the rock prior to its deformation was not very like the normal quartzite represented in the upper part of the plate, but must have been a much “dirtier” example. Again, the deformed volcanic breccia in plate xlv. should have been placed side by side with a normal specimen. Indeed, throughout the book 366 Reviews—J. J. Harris Teall’s Petrography. we think the author leans a little too much upon dynamic metamor- phism, real or supposed. Thus, there is only one figure illustrating contact metamorphism in a sedimentary rock, and that is the some- what abnormal case of the chiastolite slate of Skiddaw. We should have gladly seen with it an example of the mica-andalusite rock which occurs in the same region nearer to the intrusive granite. But when one remembers the exceptional difficulties under which Mr. Yeall has accomplished his task—for the failure of the first publisher threatened to shipwreck the book, at a comparatively early stage of its issue, and the author has completed it, at hisown risk, without any hope of profit, and with more than a possibility of loss—it seems ungenerous to cavil at minor blemishes, for the book now comes almost as “a gift-horse.” é So we will allow ourselves but one other criticism. The title of the work does the author an injustice—it is not a Petrography, but a Petrology. No doubt, as he says, the work is to a large extent devoted to a description of the rocks so far as this is dependent on the examination of hand specimens; but the significance of the structures and of the relations of the minerals are again and again discussed ; indeed, the chapters on the characters and classification of igneous rocks, on their origin, metamorphosis, and destruction, are of the highest value. We lay some stress on this verbal question, because the confusion between the two terms Petrography and Petrology is so common, especially among continental writers. Perhaps the author would thus defend his selection of a title; but we have yet to learn that “following the multitude to do evil” isa valid excuse in science any more than in ethics. The distinction between a “graphy” and a “logy” is indisputable, for it rests on the inherent significance of words—and no concurrence of authors, however eminent in science, can alter this. The ‘“ petrographer” must be content to walk with the geographer and shake hands with the photographer; to receive only a bow of condecension from the mineralogist and the geologist. The dominant principle of Mr. Teall’s work we believe to be a thoroughly sound one. It is, that to give an accurate description of a rock is a vastly more important matter than to give ita name. A rock type is to be regarded as the ‘locus’ in which a group of characteristics meets, as a convenient expression of a complex idea, rather than as a distinct entity. Hence, though we are obliged to name, and are bound to define with some precision, our ideal types, though it is unpardonable to misapply their names—as, for instance, to call a rock a serpentine when it contains much silicate of alumina and comparatively little silicate of magnesia—still our species, as we may call them, should be made as inclusive as possible, and preci- sion should be obtained rather by addition of epithets than by novelty in nomenclature. The first chapter of the book gives an admirably clear sketch of the constituents of igneous rocks, describing their various forms, microlithic and otherwise, together with an outline of the work which has been done in the study of inclusions in minerals and the Reviews—JI. J. Harris Teall’s Petrography. 367 significance attached to them by various workers. Succeeding chapters summarize the chemical and physical characters of igneous rocks, giving a brief notice of the uses made of certain chemical solutions in separating rock constituents, and determining their specific gravity. Indeed, we may say that in every part Mr. Teall appears to have brought up his information to the latest date, though he wisely abstains from burdening his book with long descriptions of methods of investigation, chemical or physical. Next comes the classification of igneous rocks, where the principle already noticed is enunciated. The author also discusses the vexed question of geological age as a primary factor in classification of igneous rocks. Here British petrologists have for some years been at issue with most of their fellow-workers on the Continent. Of the ultimate result of the contest there can now be little doubt. Mr. Teall takes this position, “‘ While declining to accept geological age as a primary factor in classification, . . . the present writer is strongly of opinion that, if possible, it should receive indirect ex- pression. . .. So when any peculiarity of texture or composition can be shown to characterize rocks of a particular period, that peculiarity should be utilized for purposes of classification.” To this concession no reasonable objection can, in our opinion, be made: probably, however, it will be rarely of avail in practice. The succeeding chapters describe the more important varieties of igneous rocks. This portion of the book will be found by the student a perfect mine of valuable information very lucidly arranged. Mr. Teall has mastered the voluminous literature of the subject, and gives an admirable summary of the result of his studies. His un- wearied patience and assiduity will cause future workers to invoke blessings on his name, and to save them from being crushed, to use Professor Huxley’s metaphor, beneath the gifts which have, been heaped upon them; gifts, among which, as in the case of Tarpeia, there is much metal of greater weight than worth, as well as the gold. This sketch is to a certain extent critical as well as historical, as it should be, but it is executed, as a rule, in a thoroughly judicial spirit. If the author shows any bias, it isin an occasional disposition to regard dynamic metamorphism too much as an established theory rather than a probable hypothesis. Perhaps also it would have been well to have mentioned that in some cases where foliation is claimed as the result of regional or dynamic metamorphism, difficulties have been indicated and other hypotheses suggested. Still, this potent factor of change has been so overlooked of late years, that we are glad to see the student’s attention called to it, It must hold a prominent place in future among the agencies of metamorphism, though we doubt whether Ecpiesis will ultimately enjoy a supremacy “quite as universal as seems at present to be claimed by some of her newly-converted devotees! Under each principal group the author describes the different examples and varieties of igneous rocks, according to their geographical distribution, thus adding to the utility of his book as oO a work of reference. There is a particularly valuable sketch of the 368 Reviews—Geological Survey of Canada. ‘Mica Traps.’ The nepheline rocks of course can only be illustrated by the well-known example from the Wolf Rock, and for a leucite rock the author has had to go beyond the limits of the British Isles. Here we think a better example might have been found for figuring than that which he has selected. The principal types, however, are all briefly described in the text. There is an excellent chapter on Contact Metamorphism, and that which follows, on the origin of Igneous rocks, is one of the most valuable in the book; for it contains a discussion of the experiments by the late lamented Prof. Guthrie, on eutectic solutions, and of the no less important researches of Lagorio on the crystallization of minerals out of igneous magmas. The work concludes with a discussion of the metamorphoses and destruction of Igneous rocks, which is to some extent a summary of questions touched upon in the body of the work. Dr. Hatch has contributed a glossary of terms used in describing rocks, for which also the student should be duly grateful, as its compilation must have cost much labour of a rather dull kind. We have not attempted to give a full summary of this admirable work. Its 422 large octavo pages are so replete with valuable matter, that this would be impossible, and we have no disposition to save the student from the labour, no less profitable than pleasant, of reading the book. It is one which every geologist who desires accurate information on the structure of our igneous rocks should have upon his shelves. We have frankly ventured one or two small criticisms, but we wish it to be understood that these relate in the main to questions where, doubtless, the personal equation come in, with the reviewer as well as with the author—and conclude by no less frankly asserting that it bears on every page testimony of the most conscientious labour, and is not only a careful compilation, but also full of the results of original research. Knowing well Mr. Teall’s abilities and learning, we had expected much, but we have found more. Henceforth he will hold a place in the foremost rank not only of petrographers but also of petrologists. T. G. B. IJ.—Rerort on a Part or NortrHErRN ALBERTA, AND PoRTIONS or Apgacent Districts or ASSINIBOIA AND SASKATCHEWAN. By J. B. Tyrrett, B.A., F.G.S.; pp 1 E to 176 E, with Appen- dices i—iv and two Maps. (Geological and Natural History Survey of Canada, Part E, Annual Report for 1886; Montreal, 1887.) oh this report Mr Tyrrell furnishes us with an account of the geology and natural resources of the tract surveyed and points out the “extent, position and character” of its mineral deposits. I'he country traversed “lies between the 51st and 54th parallels of North latitude, from longitude 110° to 115° 15’ west, including an area of over 45,000 square miles.” The author begins (p. 7 E) with a brief history of former explorations, among which the most im- portant of the earlier ones was that carried out by Captain Palliser, with Dr. Hector as Geologist (1857-1859). These pioneer explorers were followed by many others, some of whom, like Milton and Reviews — Geological Survey of Canada. 369 Cheadle, and W. F. Butler,? have made this vast region familiar to many readers by the graphic descriptions they have. given of their journeyings through it; while Selwyn (1878), Ells (1875), and G. M. Dawson (1879) have added much to our knowledge of its geology. The physical features of the country are treated of in detail by Mr. Tyrrell (pp. 14 E to 56 EK) ; but we have space only for avery brief extract from this part of his report. We learn that “‘the general character of the country is that of a sloping plain, breaking into abrupt ridges to the south-west, where a small area of foot-hills is included. From the base of these hills, which attain a height of 5000 feet above sea-level, the country declines to the north- east, sloping off from an altitude of 4000 feet, along the eastern edge of the foot-hills, to 1650 feet at Fort Pitt, on the Saskatchewan, The slope, though fairly regular, taken as a whole, is, however, broken by numerous high hills and deep river channels.” The rock formations dealt with in the report, under the head of “Descriptive Geology” (pp. 56 E to 126 KE), are enumerated in the following table in descending order :— Post-TERTIARY. Feet. Recent Deposits.—Sands, Clays, etc. Upper Boulder Clay.—Light-grey sand, and, ‘eenerally, ‘indistinctly stratified clay, with pebbles of gneiss, quartzite, ete. Lower Boulder Clay.—Dark-grey, “thick - bedded, or massive, ‘sandy clays, containing pebbles of quartzite, etc., ‘and numerous frag- ments of lignite Pebble Bed.—Quartzite shingle, lying i in a loose sandy matrix MrI0cEne. Gravels, fine sands and argillaceous marls, the gravels sometimes cemented into a hard conglomerate. . c < : C 270 Laramie. a, Paskapoo Series.—Grey and brownish-weathering, lamellar or massive sandstones, and olive sandy shales; an exclusively fresh- water deposit . 5700 b, Edmonton Series.—Soft ‘whitish sandstones and white or ‘grey, “often arenaceous clays, with bands and nodules of clay ironstone, and numerous seams of lignite; a brackish-water deposit . c 700 Fox Hitt anp Pierre, Brownish-weathering sandstones and dark-grey clay-shales . : : 600 Betty River Serres. Soft, whitish sandstones and arenaceous clays, changing towards the east to light-brownish and ae sandstones and andy al bottom not seen. “No intrusive rocks occur anywhere ehrouphout the district and below the top of the Laramie there is no evidence of any uncon- formity between the different formations. a Belly River Series.—Owing to the unfossiliferous character of the beds and the scarcity of sections, the exact boundaries of this series could not be accurately defined. The only fossils found were a few fresh-water genera, Unio, Spherium, etc., and fragments of the leaves and wood of plants. No workable coal-seams were found. t “The North-West Passage by Land,” 1863. 2 “The Great Lone Land,” 1873. 3 Described by Sir W. Dawson in Trans. Roy. Soc. Canada, 1887, Sect. iv. p. 31. DECADE III.—vVyOL. V.—NO. VIII, 2k 370 Reviews—Geological Survey of Canada. Fou Hill and Pierre Group.—The Fox Hill sandstone and the Pierre shales were found to be so completely interbedded as to make it impossible to separate them, the yellow sandstone at the top of the group being precisely similar to that at the bottom, and holding, moreover, the same fossils, viz. Placenticeras placenta, Teredo burrows, etc. A large series of characteristic fossils was obtained, some of them being new to science.! No workable beds of coal were found within the district surveyed. Edmonton Series.—TVhis is regarded as the most characteristic series of the whole region, “for though its thickness, wherever. determinable, was never found to exceed 700 feet, the horizontal position of the strata causes it to underlie a very large extent of country ” from the outcrop of the “‘ Big Coal Seam,” on the North Saskatchewan, “to or alittle beyond its easterly bend north of the Beaver Hills; and stretching a little south of east to Red Deer River in the vicinity of the Hand Hills, comprising the lower part of the bold escarpment, which there forms the south-western boundary of these hills.” Extensive Coal-beds were found on this horizon, which, commencing as a ‘thin bed of carbonaceous shale, attained on the North Saskatchewan a thickness of 25 feet. Gold was found in paying quantities disseminated through the rocks in the vicinity of the “ Big Coal Seam” on the North Saskatchewan. It is washed out of the sandstone and clays, and “settles with the heavier sand and gravel on the bars running out into the stream.” Regarding the derivation of the gold in the Saskatchewan, it has been held? by Dr. Selwyn that it was not derived from the moun- tains at the source of that river, ‘“‘ but rather was washed out of the soft rocks which form its banks, after it leaves the harder strata of the mountains. . . .” (p. 134 E.) The bottom of the Edmonton Series rests conformably upon the Pierre Shales, “without any sharp line of demarcation between the two,” the shales gradually losing their massive character, and chang- ing insensibly into thin beds, of brackish-water origin. | Whereas in the Pierre group remains of land plants and animals were of rare occurrence, traces of land plants and fragments of the teeth and bones of Dinosaurs were met with in considerable abundance in the series under discussion. The last-named fossils were submitted to Professor Cope for determination. The rest of the fossils included Molluses of the genera Ostrea, Unio, Corbicula, and Panopea, and plants consisting of Trapa, Salisburia, and Carpolithes, together with fragments of exogenous leaves and wood of Sequoia and Thuja. Paskapoo Series.~—The author thus designates ‘all the Laramie rocks lying above those of the Edmonton series,” and he therefore includes Dr. G. M. Dawson’s “ Porcupine Hills and Willow Creek series, and all but the lowest 700—900 feet of his St. Mary River 1 These are described by J. F. Whiteaves in Appendix I. of the Report, p. 153 E. 2 See Geol. Surv. Rep. for 1873-74, p. 58 (Montreal). ° From the ‘‘ Blind Man,” or ‘‘ Paskapoo ’’ River, which flows into the Red Deer rie from the north-west, over rocks of the Paskapoo or upper subdivision of the aramie, Reviews—Geological Survey of Canada. 371 series.” Its thickness on Little Red Deer River was ascertained to be at least 5700 feet, “the bottom of the formation not being seen, and a considerable thickness having been probably removed from the top by denudation. The whole series was proved by its fossil fauna to be of freshwater origin, shells of the genera Unio, Spherium. Limnea, Physa, Goniobasis, etc., attesting this fact. Fossil plants of the genera Sequoia, Taxodium, Platanus, Quercus, Populus, Salix, Viburnum, ete., were also collected. It will be observed in the table of strata above, that the Edmonton and the Paskapoo series are given as subdivisions of the Laramie, the former representing the Lower Laramie of the Canadian Geolo- gical surveyors, and the latter the Upper. The physical conditions under which these two series were deposited are thus described :— In the Edmonton series, which succeeds the marine beds of the Upper Cretaceous, Mr. Tyrrell finds abundant evidence of the brackish-water origin of this series, in the presence of beds of coal, fragments of land plants, and brackish water molluscs, besides numerous bones of Dinosaurs, ‘“‘ which have evidently been entombed in the beds over which they waded, or in the marsh on or along the edge of which they used to feed, or hunt their prey.” He concludes, therefore, that this series ‘‘ was laid down in shallow brackish water in an almost land-locked bay, or in a great salt marsh near the mouth of a large river... .” “At the close of the Edmonton period, the pressure which had caused the uprising of the present plains-area from the bottom of the Pierre sea, and which towards the west had raised the land com- pletely above the surface of the water, was relieved by the uplifting of the Rocky Mountains along a line near the western edge of this great area, and the “plains” sank again beneath the surface of the sea, now cut off entirely from the main ocean, and converted into a great inland lake, and a thickness of several thousand feet of sand- stones and sandy shales was laid down on the gradually sinking floor; these sandstones and shales being the Paskapoo series of this report. ae No Dinosaurian remains were discovered in these beds, but a number of land plants, land and fresh-water molluscs, with occasional beds of coal occur in them. The Laramie beds suffered a considerable amount of denudation at the close of their deposition, during a period of elevation which took place before the Miocene beds began to be laid down. From all these facts Mr. Tyrrell deems himself justified in con- cluding that the Cretaceous Epoch terminated with the deposition of the uppermost beds of the Edmonton series; and that the Tertiary Epoch began with the commencement of the Paskapoo period, which he regards as “the representative of the Hocene of Europe,” an opinion held also by Dr. Newberry.} Concerning the exact age of the Laramie little can be affirmed with certainty. We have seen what Mr. Tyrrell’s views are upon the subject; it may be profitable now to consider those of some 1 Trans, New York Academy, Feb. 1886, O12 Reviews—Geological Survey of Canada, other geologists. The question has been attacked with much ability and mastery of details by Mr. Lestey F. Ward, in a “Synopsis of the Flora of the Laramie Group.”* This writer gives it as his opinion that “it is wholly immaterial whether we call the Laramie Cretaceous or Tertiary, so long as we correctly understand its relations to the beds below and above it. We know that the strata immediately beneath are recognized Upper Cretaceous, and we equally know that the strata above are recognized Lower Tertiary. Whether this great intermediate deposit be known as Cretaceous or Tertiary is therefore merely a question of a name, and its decision one way or another cannot advance our knowledge in the least.”” Sir William Dawson, in his memoir on the “ Fossil Plants of the Laramie Formation of Canada,’”? concludes “that we must either regard the Laramie as a transition Cretaceo-Eocene group, or must institute our line of separation in the Middle Laramie division, which has, however, as yet afforded no fossil plants.” Miocene.—“ Resting on the denuded edges of the Laramie in the Hand Hills, are beds of light-grey argillaceous marls inter-bedded with fine grained sands, which pass upwards into a bed of quartzite pebbles, in some places held together by a hard calcareous cement, and forming a compact conglomerate.” No fossils were found in this formation, but from its position and character it was judged to be of the same age as the Miocene of the Cypress Hills, described by Mr. McConnell in 1884.° Post-Tertiary.—The following are the subdivisions of this forma- tion, distinguished by Dr. G. M. Dawson, which hold good also in the area explored by Mr. Tyrrell :—“ Stratified sands, gravels and silts. Upper boulder-clay. Interglacial deposit with peat. Lower boulder-clay. Quartzite shingle and associated beds.” These beds overlie the greater part of the region examined in “an extensive, though generally thin, sheet,” filling up the irregularities in the surface of the Cretaceous and Laramie rocks, and forming also many of the rolling hills. Economic Minerals.—First in importance are the extensive deposits of Coal and Lignite which underlie an area of more than 12,000 square miles in the western part of the district surveyed. Of bituminous coal, a seam near the Bow River is estimated to contain about 9,500,000 tons of coal to the square mile. Of the lignitic or semi-bituminous coals, the seam on the North Saskatchewan River was computed to contain over 150,000,000 tons. The occurrence of Gold in this river has already been noted. This valuable report closes with four appendices, the first con- taining descriptions by J. F. Whiteaves of the fossils collected by Mr. Tyrrell (1885 and 1886) in the Cretaceous and Laramie Rocks ; the second, * Lists of Lepidoptera,” by Mr. James Fletcher; the third, “List of Elevations”; the fourth, “Cree and Stoney Indian names for places within the area of the accompanying map.” It Sixth Annual Rep. of the United States Geol. Surv. 1884—85, Washington, 1885. 2 Trans. Roy. Soc. Canada, Sect. iv. 1886, p. 19. 3 Geol. Surv. Rep. Canada, for 1882—84, p. 140 C. Reviews—Dr. Georg Baur’s Fossil Chelonia. 373 may be added that the maps accompanying the Report are drawn to a scale of seven geographical miles to one inch. One illustrates the geology, the other marks the wooded and prairie tracts of the country embraced in the report. INS al, int IIJ.—Dr. Grore Baur on Fosstn Cueronta. HE publication of preliminary notes and synopses of results is often desirable, as affording the opportunity of criticism before the completion of any extensive work ; and it is sometimes a con- venient method of securing valuable co-operation from other workers in a given field. But when indulged in to so great an extent as is now unfortunately the custom in some quarters, the practice becomes both confusing and annoying; and the steady progress of science degenerates into a mere struggle for “priority,” burdened with endless unfinished notes and crude speculations. Such considerations are once more suggested by Dr. Georg Baur’s latest remarks upon the Paleontology. ‘of the Chelonia. Entombed in the form of a footnote to a four-page pamphlet upon the origin of the paddles of the Ichthyopterygia,’ is the definition of a supposed new genus of Chelonia from the Keuper Sandstone of Wiirtemberg! The fact is one of considerable interest, and the fossil of the greatest importance ; but the future historian of the Chelonia is hardly to be blamed if he fails to discover the “priority ” of the name Proganochelys Quenstedtit, when referring to this unique fossil: one author, indeed, in another “preliminary note ” upon the same specimen,” has already overlooked both the description and the name. The fossil is a natural internal mould of the carapace and plastron of a Chelonian, especially remarkable for its high degree of specialization; and it is not improbable that, when more is known of the animal, it will prove to be identical with Chelytherium obscurum, von Meyer. The plastron is described as completely closed, and united laterally with the cara- pace, without any fontanelles. The next reference to Proganochelys occurs in a letter ® announcing the discovery of small dermal ossicles upon the limbs of Testudo Leithii, where the interest of the genus is remarked upon in connec- tion with the controversy as to the systematic position of the Athecan Chelonia: and then the subject of ‘“ Unusual Dermal Ossifications ” suddenly develops into the definition of another new genus, founded upon the well-known “ Chelone”’ Hojffmanni of the Maastricht Chalk. Dr. Baur proposes henceforth to place the latter in a genus named Allopleuron, on account of the small development of the costal plates and the narrowness of the marginals. 'The results are most interest- ing and worthy of consideration, but it is not too much to ask that in future we may have the subjects under recognizable titles, even if it is still considered desirable to publish them in so obscure and scattered a form. JX tsp \io 1G. Baur, ‘‘ Ueber den Ursprung der Extremitiaten der Ichthyopterygia,’’ Bericht xx. Versamml. Oberrhein. geol. Vereins, 1887. 2 Zarszewski, ‘‘ Kine im Stubensandstein des Keupers gefundene Schildkréte,”’ Wiirtt. Jahresh, 1888, p. 38. : me Baur, ‘* Unusual Dermal Ossifications,’’ Science, March 28rd, 1888 (vol. xi. p: : ov4 Reviews—Prof. J. S. Newberry—On Edestus. IV.—On tee Srructure anp Rewtations or Hprstus, WITH A Description oF a Gigantic New Spescizs. By Prof. J. 8. Newserry, M.D. (Annals New York Acad. Sci. vol. iv. No. 4 (1888), pp. 1-10, pls. iv.-vi.) HE discovery of a new gigantic example of the remarkable fossil spine, Hdestus, in the Coal Measures of Mason County, Hlinois, affords Prof. Newberry the opportunity of again reviewing the characters and possible relationships of this anomalous fish- fragment. ‘The memoir is one of much interest, and refers to nearly all the points hitherto ascertained, except Trautschold’s discovery of the occurrence of the fossil in Russia. It would, however, have added much to the completeness of the discussion, if a microscopical section had been prepared ; for if Hdestus consists of ‘‘ dense bone” (p. 0), it is certainly not a Selachian dermal appendage, and if it has the well-known structure of the latter, it is useless to speculate as to its pertaining to a Ganoid (p. 4). From various other considera- tions, Prof. Newberry concludes that the original fish must have been a Selachian; and the fossil is regarded as an undoubted spine. The latter must have been “ buried in the integuments throughout its entire length; the enamelled denticles alone projecting above the surface to form a saw, which would be a terrible weapon, if placed upon some flexible portion of the body where it could be used with freedom and power. ‘The extremity of the spe may have lain in a sheath from which it could be partially erected by muscular action, and used as the lancet of the surgeon fish (Acanthurus) is; but the bilateral symmetry of Edestus proves that if employed in this manner it must have been located on the upper margin of the tail or back.” The arrangement is considered to be best explained—perhaps precisely paralleled —by Trygon, in which “‘a considerable number, sometimes five or six, defensive spines are set in the place of the posterior dorsal fin. They come into use in succession, like the fangs of venomous serpents. As the anterior one loses its denticles or becomes worn or broken, it falls, and is succeeded by another from behind. Yet several may be in existence and effective at the same time, all arising from a common segmented bony base which grows by additions to its posterior extremity.” The new spine of Hdestus giganteus is at least 18 inches in length, by 74 inches in breadth, and indicates the enormous dimensions to which the fish must have attained, if this ingenious explanation proves true. ACTS sie FEwEs @ ive SS) AlN eb) | ee © Czar D> aie iS ——_@—_—__ GEOLOGICAL Society or Lonpon. J.—June 6, 1888.—W. T. Blanford, LL.D., F.R.S., President, in the Chair.—The following communications were read :— 1. The following letter from H.M. Secretary of State for India accompanying some specimens of rubies in the matrix from Burmah :— “India Office, Whitehall, S.W., 2nd June, 1888.—Sir,—I am: directed by the Secretary of State for India in Council to present to Reports and Proceedings—Geological Society of London. 375 the Geological Society some specimens of Burmese rubies attached to their matrix, which were procured by Mr. Barrington Brown, at present employed by Government in examining the mines which came into their possession on the annexation of Upper Burmah.”— Mr. Barrington Brown writes concerning these specimens thus :— ‘IT send . . six specimens of rubies in granular limestone, where they were formed. They were obtained by blasting, under my direction, in a place formerly mined by natives... . As I believe the fact of the ruby being traced to its matrix is new to science, the specimens may prove of interest to scientificmen. . . . I should like Professor Judd, President of the Geological Society, to see the speci- mens.’—I am, Sir, your obedient servant (signed) J. A. Godley.— Bern Geological Society.” “On the Sudbury Copper Deposits (Canada).” Byido) He sateen Hsq., F.G.S: These deposits occur in Huronian rocks. The author described two exposures, known as Copper Cliff and Stobie, about 8 miles apart. At the former the ore was found in the face of a cliff of diorite about 40 ft. high. The ore exists in three distinct forms :— 1. As local impregnations of siliceous and felspathic beds of clastic origin, in the form of patches and strings of cupreous pyrrhotite. 2. As contact-deposits of the same material lying between the im- pregnated beds and large masses of diorite. 3. As segregated veins of chalcopyrite and of nickeliferous pyrrhotite, filling fissures and shrinkage-cracks in the ore masses of the second class. The author considered the first as original, or of high antiquity ; whilst the two latter are due to segregation produced either by intru- sion of diorite, or by internal movements. He compared these deposits with those of Rio Tinto of Devonian age, showing their similarities and differences. At the latter place the intrusive masses are quartz- porphyries, and the metallic deposits consist mainly of bisulphide of iron. The ore-bodies in the Canadian deposits are not so large. From the cupreous pyrrhotite of Sudbury, rich though it be, com- pared with the Rio Tinto ore, the copper cannot be so cheaply ex- tracted by the wet method, and the ore is of no avail as a source of sulphur. Nickel is everywhere present in the cupreous pyrrhotite of Sudbury, and of no advantage to the smelter. The differences above recorded are probably not due to differences in the containing rocks, since similar differences may be noticed in the pyritous deposits of Canada, where the country rocks are identical. 3. “Notes on some of the Auriferous Tracts of Mysore Province, Southern India.” By George Attwood, Hsq., F.G.S., F.C.S., ete. _ The author was employed during parts of 1886-7 in inspecting a large area of mineral lands in Southern India supposed to be auriferous, and the paper contained the results of his observations. 1. Melkote Section. —This section (in the Hassan district of the province of Mysore), starting one mile west of Melkote in a north- easterly direction, exposed gneiss, mica-schist, hornblende-schist, 376 Reports and Proceedings— quartzite, tale- and chlorite-schists, eclogite, and quartz veins, striking generally N. 20° E., and having varying dips. The eclogite was described at length, and special attention was called to the flattening of the contained garnets, which were probably originally almandite ; other evidences of great crushing were also noted. In this section and on most of the schistose lands of Mysore a dull grey, nodular, and botryoidal calcareous deposit, known as “kunkur,” is found in nullahs, on hill-sides, and on the detritus of old gold washings, and it was suggested that the contained lime was derived in great measure from hornblende-schists. Many quartz outcrops, large at the surface but diminishing in thickness downwards, were met with at the east end of the section ; these veins have a strike about N. 15° EK. to N. 20° E., coincident with that of the schists. Extensive gold-washings have been carried on in the ravines and hill-sides, and the mode of occurrence and character of the gold were described. The author considered the schists, as well as the quartz veins, to belong to very old series of rocks, probably Archean. 2. Seringapatam Section.—The second section was taken in a south-easterly direction from the 72nd milestone on the Seringapatam and Bangalore road to the N.W. side of the village of Arakere. Gneiss, hornblende, and mica-schists, ete., were here met with, striking about N. 20° E. with varying dips. These were traversed by auriferous quartz-veins which had been largely worked, and the author gave a description of the former methods of extracting the gold. At the 8.E. end of the section the schists were found to be much broken by porphyrite dykes of much more recent origin, most likely of Tertiary age. A small granite dyke intersected the Elliot Lode diagonally, and was considered to be of Upper Tertiary age. 3. General Observations.—The author described the results of traverses of other districts; he pointed out the evidences of great pressure which had broken up the gneissic rocks and compressed the schists, and conjectured that this might have been produced by the gradual rise of the Eastern and Western Ghats, and finally called attention to the great denudation which the Mysore plateau had undergone. An Appendix by Prof. T. G. Bonney, D.Sec., LL.D., F.R.S., F.G.8., gave an account of the microscopic characters of the schists, the flattened garnets, the porphyrites, etc., and in this it was pointed out that one set of rocks belonged to an ancient series which, even if wholly or in part of igneous origin, assumed their present mineral structure and condition at an epoch remote from the present, whilst another set was certainly igneous and of more recent date. 4. “On the Durham Salt-district.” By E. Wilson, Esq., F.G.S. In this paper the author described the new salt-field in the North of England, occupying the low-lying country bordering the estuary of the Tees, and situated partly in Yorkshire and partly in Durham. The history of the rise and progress of the salt-industry in South Geological Society of London. B17 Durham was given, since the first discovery of salt by Messrs. Bolckow, Vaughan & Co. at Middlesboro’, in the year 1859. The stratigraphical position of the saliferous rocks of the Durham salt-district was considered in some detail. The diverse views which have been previously expressed on this head were referred to, and reasons given for concluding that all the beds of rock-salt which have been hitherto proved in this field, and the red rocks with which they are associated, belong to the upper portion of the Trias, viz. to the Upper Keuper series (Waterstones subdivision). The probable area of this salt-field, the limits of the distribution and varying depths of the chief bed of rock-salt, were indicated, and the extent of its supplies pointed out. In conclusion, the author called attention to the waste, as well as to certain other disadvantages resulting from the process of winning the salt now in operation. 5. “On the Occurrence of Calcisphere, Williamson, in the Carboniferous Limestone of Gloucestershire.” By E. Wethered, Esq., F.G.S., F.C.S. The small hollow spheres, with varying forms of peripheral appendages, described by Prof. Williamson as Calecisphare, were found in the Carboniferous Limestone of Flintshire, and were suggested by him to be possibly Foraminifera or the reproductive capsules of some marine form of vegetation, although he admitted that no forms hitherto discovered afforded any definite support to this hypothesis. Prof. Judd expressed a belief that the objects were Radiolaria; whilst Mr. Shrubsole discovered similar bodies in the Mountain Limestone near Llangollen, and conjectured that the described forms included both Foraminifera and Radiolaria. The author has discovered the Calcisphere in great numbers in the Carboniferous Limestone of Gloucestershire. He discussed the identity of certain calcareous rings ‘005 in. in diameter, seen in sections of the limestone of Clifton, etc., with siliceous bodies which he had described in a recent paper read before the Society, and gave an account of the calcareous and siliceous forms which were both referable to Calcisphere. He commented upon the character of the carbonate of lime of the calcareous bodies, which presented a granular structure characteristic of the truly organic portion of the limestone, and not a clear crystalline aspect like that of the infilling or re- placing calcite; he concluded therefore that the tests had been originally calcareous, and not siliceous replaced subsequently by carbonate of lime. This was urged as a strong argument against regarding the organisms as Radiolaria, and the author, whilst considering it unwise to come to a decided conclusion, believed it safe to say that they were Protozoa. 6. “Second Note on the Movement of Scree-material.” By C. Davison, Esq., M.A. Communicated by Prof. T. G. Bonney, D.Sc., F.R.S., F.G.S. After briefly recapitulating the substance of his previous paper, the author now communicated the results of experiments continued for a year. He gave a figure in which a continuous line represented, 378 Reports and Procecdings— in millimetres, the movements of the upper stone from week to week, whilst a contiguous dotted line indicated the mean ranges of temperature. The rate of descent does not depend solely on the mean range. He gave the following comparison of rates of descent :— Average daily range Total mean descent Rate of descent in of temperature. in millim. inches per day. Summer, 184 days...... 14°-4 F 8 ‘00171 Winter, 182 days ...... 8°-0 OF 00121 Thus the changes are not altogether proportional to the ranges of temperature, being relatively higher in the winter months. In considering the influence of rain, he observed that its effects are to slightly increase the rate of descent by diminishing the coefficient of friction, and by lowering the temperature, both as being itself generally colder than the air on the ground surface, and also owing to evaporation. He likewise observed that the rate of descent was nearly doubled during the latter part of the winter, chiefly owing to the effects of snow. IJ.—June 20, 1888.—W. T. Blanford, LL.D., F.R.8., President, in the Chair.—The following communications were read :— 1. “On the Occurrence of Marine Fossils in the Coal-measures of Fife.” By James W. Kirkby, Esq. Communicated by Prof. T. Rupert Jones, F.R.S., F.G.S. This paper recorded the discovery of fossils of good marine types in the Fifeshire Coal-measures. This coal-field is of limited extent, the Coal-measures dipping under the sea towards the east and south. The prevailing fossils are those characteristic of the Coal-measures in other districts, Anthracosia, Anthracomya, Anthracoptera, Spiror- bis, many fishes, and some few Amphibian remains. Lately a sink- ing was commenced in the Upper Red beds, below which, and just above a thin band of poor coal, a thick bed of dark shale was passed through, which proved to be tolerably fossiliferous. Lingula, Mureli- sonia, and two species of Bellerophon occurred. This horizon was subsequently proved elsewhere in the district, and furnished the following fossils from three localities, namely :—Sitrephodus sau- roides? Ag. (teeth and scales) ; Rhizodopsis, sp. (scales) ; Paleeoniscid scales; Diplodus gibbosus, Ag.; Mesodomodus, sp. n.; Petalodus Hastingsia ; Discites rotifer ? Salt.; Discites, sp. (with longitudinal ribs) ; Discites, sp. (smooth); Orthoceras attenuatum? Flem.; Lel- lerophon Urii, Flem.; Murchisonia (Aclisma) striatula, De Kon. ; Sanguinolites, sp.; Productus semireticulatus, var. Martini, Sow. ; Discina nitida, Phill.; Lingula mytiloides, Sow.; Lingula squaini- formis ; Crinoid stems (Actinocrinus ?) ; Plant-remains (obscure). Reference was then made to the occurrence of similar fossils in the same formation elsewhere, and particularly in the West of Scotland, North of England, and Lancashire. The author concluded, from the frequency of the beds containing true marine remains, that the Coal-measures were formed in low-lying areas; and that, when the land was slightly depressed, at times the waters of the sea had Geological Society of London. O79 access to such spots, bringing back species of shells and Crinoids that had existed in the Carboniferous-Limestone ocean of an earlier period. Some further remarks were made on the peculiar nature of the ordinary fauna of the Coal-measures; and the author observed, in conclusion, that no marine deposits have been observed as yet in the Upper Red beds (d°') of the Fife or other Scotch Coal-measures. 2. “ Directions of Ice-flow in the North of Ireland, as determined by the Observations of the Geological Survey.” By J. R. Kilroe, Esq. Communicated by Prof. E. Hull, F.R.S., F.G.S. While the strie S.E. of a line drawn from Strangford Lough to Galway Bay all trend in one direction, two sets of strizw occur N.W. of that line, which are generally at right angles to each other, and are frequently seen upon the same rock-surface. The direction of one of these is N. by W. in Antrim and Londonderry; N.W. over the highlands of Fermanagh; and N.E., N., and N. by W. in Donegal, etc. That of the second set is W. 25° S., swinging round to W. in Donegal and §.W. towards Galway Bay. and is strikingly persistent throughout. A few striations occur which do not conform to these directions, and are attributable to local ice-flows. The second set of striations was referred to the ice of the Scottish Glacial System, and evidence was cited from the researches of Messrs. Symes and M‘Henry, Dr. Geikie, and others in support of this view, which is confirmed by the relative positions of the boulders and their parent rocks. Strie bearing westward have been observed at a height of 1100 feet in county Mayo. The effects of the Irish Glacial System have been considered by the Rey. M. Close, Mr. G. H. Kinahan, and Prof. Hull. Striations occur up to 1340 feet in Donegal. The ice of this system flowed in a general §.H. direction to the S. of the axis. With regard to the relative age of the two sets of striz, it is observable that those bearing northward are by far the most numer- ous ; so that, although it is reasonable to suppose that a considerable accumulation of snow and ice obtained in the Irish area whilst the Scotch system was gathering its maximum strength, the striations produced by this gathering would be largely effaced by the west- ward-flowing Scotch ice; and that, after the decline of the latter, an independent Irish Jer de glace flowed northward and southward, finding its axis of movement in the great central snow-field. 3. “ Evidence of Ice-Action in Carboniferous Times.” By John Spencer, Hsq., F.G.S. The author combated the notion that there is any d priori im- probability in the action of ice during the period in question. In the case under consideration, of the two agents, land-ice or floating- ice, he was inclined to adopt the latter, as having been the cause of the phenomena he described. The bed affected is the Haslingden Flag-rock, a member of the Millstone-Grit series, which is directly covered by a shale of the same series. The surface of this Flag-rock is largely striated, the striae having a N.E. and §.W. direction, and being nearly parallel. The area exposed is 2U0 square feet. The Flag-rock dips to the east at an angle of 50°; but there seems no possibility 380 Reports and Proceedings— of these strize having been produced by landslips or local disturbance. A quarry on the same horizon, near Rochdale, exhibits similar phe- nomena. As collateral evidence of ice-action, he alluded to the boulders frequently found in the coal-seams. 4. “The Greensand Bed at the Base of the Thanet Sand.” By Miss Margaret I. Gardiner, Bathurst Student, Newnham College, Cambridge. Communicated by J. J. H. Teall, Esq., M.A., F.G.S. This bed may be seen between Pegwell Bay on the east and Chislehurst on the west, and a somewhat similar bed occurs at Sudbury, Suffolk. An examination of the Kentish layer showed it to consist of 45 per cent. of quartz, 15 per cent. of glauconite, and ° 40 per cent. of flint. Amongst the rarer minerals are felspar, magnetite, spinel, zircon, garnet, rutile, tourmaline, actinolite, epidote, and chalcedony; and there are a few microscopic organisms, either Radiolarians or Diatoms, and some Foraminiferal casts. The Sudbury Greensand has 75 per cent. of its grains consisting of glauconite, and of the quartz- and flint-grains only 10 per cent. are flint ; several of the rarer minerals found in Kent occur here also. The large flint-percentage in the Kentish grains was alluded to in support of the existence of an unconformity at the base of the Tertiary deposits of that area; and the relatively small percentage of flint in the sands now being formed along a very similarly situated shore was suggested to be due to the drifting débris derived from the coasts composed of Tertiary and Wealden rocks, which became mixed with the material brought down by the Thames. 5. ‘On the Occurrence of Elephas meridionalis at Dewlish, Dorset. By the Rev. O. Fisher, M.A., F.G.S. The author’s attention was first drawn to this subject on seeing two molars of an elephant in the Blackmore Museum labelled ‘« Dewlish, Dorset.” He at once attributed them to EH. meridionalis. Subse- quently he ascertained that they were part of a find made in 1818 by a Mr. Hall. Dr. Falconer, from rubbings, attributed the teeth to E. antiquus; and Dr. Leith-Adams would not allow that they belonged to EH. meridionalis, because that species had never been found so far west. Last year the author and Mr. Mansel-Pleydell went to Dewlish, and the latter has since continued the workings. The remains have been found high up on the face of a steep chalk scarp facing west, 10 feet below the brow and 90 feet above the existing stream, in such a position as to suggest that the deposit was the result of an undercut of the stream when it flowed at a higher level. It probably lies in the prolongation of a line of fault with a deviation to the east. The following section was given :— ft. in. 1. Chalk rubble... .. Hh Wl tae ce OM AIO) 2. Fine sand and flints, with elephant remains... 3 0 3. Sand and ferruginous gravel.. Scape ees 2 4, Flint-material, “waterworn ... a0 p 5. Sand, the lower portion with different-sized flints P There were no shells or Microzoa. The author speculated on the probable lapse of time, and on the importance of the discovery of E. meridionalis, a pre-glacial mammal, so far west. A list of the bones found was given. Geological Society of London. 381 6. “On Perlitic Felsites, probably of Archean Age, from the Flanks of the Herefordshire Beacon, and on the Possible Origin of some Epidosites.” By Frank Rutley, Esq., F.G.S. The author has previously described a rock from this locality in which faint indications of a perlitic structure were discernible. In the present paper additional instances were enumerated and a description was given. The perlitic structure is difficult to recognize, owing to subsequent alteration of the rock. Decomposition-products, apparently chiefly epidote, with possibly a little kaolin, have been found in great part within the minute fissures and perlitic cracks. The author suggested, from his observations, that felsites, resulting from the devitrification of obsidian, quartz-felsites, aplites, etc., may, by the decomposition of the felspathic constituents, pass, in the first instance, into rocks composed essentially of quartz and kaolin; and that, by subsequent alteration of the kaolin by the action of water charged with bicarbonate of lime and more or less carbonate of iron in solution, these may eventually be converted into epidosites. He regarded it as probable that the rocks are of later Archean or Cambrian age. 7. “The Ejected Blocks of Monte Somma,” Part 1, Stratified Limestones.” By H. J. Johnston-Lavis, M.D., F.G.S. Introductory.—The author referred to the Hamilton collection, now in the British Museum, and to the work of Prof. Scacchi, who enumerated 52 mineral species as having been found in the ejected blocks, and indicated the importance of these from a geological and voleanological point of view. His own collection contains over 600 specimens, showing the graduation from unaltered limestones, through various stages of change into numerous varieties of ‘true meta- morphic rocks,” which, in their turn, shade into igneous rocks more and more approaching the several modifications of the normal cooled magma of the volcano. Moreover, such rocks come from depths where they have not been affected by alterations of a secondary nature. He then gave a classification of the varieties of ejected blocks. The Tertiary rocks are but slightly metamorphosed, whilst the lime- stones of Cretaceous or earlier age afford an almost unlimited series of mineral aggregates. Physical changes have converted them into carbonaceous and saccharoidal marbles; next oxides and aluminates have separated, and silicates have been introduced. Such rocks come under the definition of accidental ejectamenta. They are only ejected when the apex of the crater-cavity, formed by an explosive eruption, extends below the platform of the volcano into the underlying rocks. He then traced the history of the eruptions of Somma-Vesuvius through divers phases, showing that it was only at a comparatively late period that limestone-fragments were blown out, though this had taken place long before the Plinian eruption. The stratified lime- stones have been chosen for the first part of this paper, because their original lithological structure acts as a guide as we proceed from a normal limestone to its extreme modifications. 382 Correspondence—Ir. T. Mellard Reade. Part I. —The character of the limestones which underlie the plat- form of Vesuvius may be studied in the peninsula of Sorrento, where the mass attains a thickness of 4700 feet. They are magnesian in varying proportions. A table was given showing twenty-seven analyses, made principally by Ricciardi, the amount of MgO ranging from 1 to 22 per cent. Silica rarely exceeds 2 or 38 per cent., where- as in the greater number of limestones it isabsent. The bituminous matter, though a powerful colouring agent, usually exists in quantities too small for estimation, but sometimes reaches 8 per cent. Such are the materials out of which the extraordinary series of silicate-, compounds have been developed, and as these materials of themselves could not form peridotes, micas, pyroxenes, etc., it is clear that the silica, alumina, iron, fluorine, etc., must have been introduced from without, viz. from the neighbouring igneous magma. The author then discussed the question of the probable methods, being inclined to favour the notion of vapour in combination with acid gases. The bulk of the paper was occupied with a detailed description of the microscopic structure of these stratified limestones and their derivatives. The author remarked that the same metamorphic changes may be traced on a much grander scale amongst the ejected blocks, and hinted at the similarity of these changes to those of contact-phenomena as seen elsewhere, and even of regional meta- morphism, the two main factors to be considered being the composi- tion of the rock to be acted upon and that of the magma acting. The changes which ensue in an impure limestone are, in the first place, the carbonization of the bituminous contents, which are con- verted into graphite; and a kind of recrystallization, approaching the saccharoidal structure, seems to have taken place, although the - stratification, etc., is preserved. A few grains of peridote now begin to make their appearance, chiefly as inclusions within the calcite crystals, and thus by degrees the results already recorded are effected. In the early stages only is the metamorphism selective. The order in which the new minerals seem to develope is the following :—(1) Peridote, Periclase, Humite. (2) Spinel, Mica, Fluorite, Galena, Pyrites, Wollastonite. _(8) Garnet, Idocrase, Nepheline, Sodalite, Felspar. Many of these minerals are crowded with microliths, which there is reason to believe consist of pyroxene. CORRESPONDENCE. a ELEVATION AND SUBSIDENCE. Str,—In the suggestion as to the cause of subsidence and eleva- tion put forward by Professor Lloyd Morgan,’ it is not quite clear whether on his hypothesis he looks upon the conversion of molten rock into the crystalline condition as a case of simple condensation by pressure following ordinary lavas, or whether he assumes that after a certain pressure is applied the molten rock will suddenly assume the crystalline condition and contract, and thereby cause 1 Grou. Maa. July, 1888, pp. 291-97. Correspondence—Mr. A. J. Jukes-Browne. 385 subsidence. For the proper estimation of the efficiency of the cause invoked, it is requisite that this should be clearly set forth. That lateral displacement by weight of accumulated sediment together with actual compression of the rocks below may take place in certain cases is extremely probable. The assumption of the existence of a zone of molten rock at a certain distance below the surface of the earth in so sensitive a con- dition as to respond to the weight of accumulation by becoming solid or that of denudation by becoming liquid is rather a large one, especially when the physical part is unsupported by experiment or quantitative determination. If these were supplied, it would be a fit subject for investigation, but the suggestion fails as a general explanation of subsidence and elevation, even if the assumptions are admitted, inasmuch as it does not account for the elevation of areas of former great sedimentation, which is one of the most striking facts of geology. T. Metiarp Reape. THE NOMENCLATURE OF AMMONITES. Str,—I had not much hope of converting Mr. Buckman from what, in common with Mr. Haddow, I conceive to be the error of his ways; but I wished to protest against the system of which he is an exponent. He still assumes that Afgoceras and Arietites are genera, which is exactly what I ventured to question. He says I do not attempt to discuss Lioceras, but I should have thought he would understand that it could be treated in the same way as Harpoceras (if it isa group of equal value). Let us write in catalogues Ammonites (Lioceras) elegans ; specialists will doubtless prefer to call it Lieceras elegans ; but most geologists will probably be content with Ammonites elegans, regarding Lioceras merely as a subgeneric name. My chief point, which Mr. Buckman entirely fails to notice, is this, that if the specialists rank Harpoceras, Lioceras. etc., as genera, each of them may be accredited with a species having the same specific name. Fancy half a dozen different Amm. elegans referable to an equal number of these so-called genera. A. J. Juxxs-Browne. “GEOLOGY FOR ALL.” Sir,— While thanking you for your notice of “ Geology for All,” perhaps you will permit me to say that what is called a “slip” is explained by the context, and is in accord with the spirit and inten- tion of the book, while the high per-centage of silica in orthoclase is duly acknowledged on page 58, where the fact is wanted. I may add that my aim was to find a new and intermediate path between the two old and well-beaten ones of Academic or Text-book geology and so-called ‘popular ” or entertaining geology, neither of which in my humble opinion is likely to lead to the end I have in view, namely, a general knowledge of geology by all well-educated people. In the days of Buckland and Hugh Miller, fossils were 384 Miscellaneous—Geological Survey of England and Wales. marvels, and these certainly attracted much attention to geology. Now they are no longer so, and from my experience, and it is not a small one, they and their nomenclature do much to restrict a know- ledge of the great teachings of geology to the limited circle to which your reviewer so justly refers. J. Logan Lospiey. City or Lonpon COLLEGE, July 16th, 1888. IMEES Grn, AGN EROmsn GEOLOGICAL SURVEY OF ENGLAND AND WALES. We are informed that Mr. H. W. Bristow, F.R.S.; has retired from the Directorship of the Geological Survey of England and Wales, after a lengthened service of forty-six years. Joining the staff of the Survey in 1842, under De la Beche, he commenced field-work in the Silurian regions of Radnorshire, and subsequently surveyed large areas of the Secondary and Tertiary strata, more especially in Somerset, Dorset, Hampshire, the Isle of Wight, and Sussex. This work has formed the basis for all later and more minute observations on the strata. The history of the Survey with which Mr. Bristow has been so long associated has been told in part in the Memoirs of Edward Forbes and Murchison by the present Director-General, and also in the Letters of Jukes ; and it is pleasant to read of the early labours of the small yet enthusiastic band of geologists, who numbered only 10 in 1844; but these included Ramsay, Warington Smyth, John Phillips, Aveline, W. H. Baily, and Edward Forbes. In the genial company of Forbes, Mr. Bristow carried on much of his detailed work in the Isles of Wight and Purbeck ; and we understand that a new edition of Mr. Bristow’s Memoir on the Isle of Wight will shortly be published. Until 1872, when he was appointed Director, Mr. Bristow was more or less actively employed in the field, devoting especial attention in these later years to the Rhetic or Penarth Beds—the latter name being given by him on account of the prominent exposures of these strata on the Glamorganshire coast. We learn that Mr. H. H. Howell, F.G.S., Director of the Geological Survey of Scotland, now undertakes the additional duties of Director for England and Wales, and his excellent geological work in the Midland counties, the North of England, and the South of Scotland, together with his well-known administrative capacity, will cause the appointment to be hailed with satisfaction. We have also much pleasure in announcing that Mr. J. J. H. Teall, M.A., F.G.S., has recently joined the staff, and is specially charged with the study of the crystalline schists and the problems of regional metamorphism. ‘churgo7 weumeyq8o\ res ; TX Id A TSA TI SRP 9S g 'Qger Sen ToeD THE GEOLOGICAL MAGAZINE. NEW. SERIESHMDECADE, til "VOLIE VE No. IX.—_SEPTEMBER, 1888. Suse MEIN (Adi) YNVISjaban Oar aay S- = I.—On a New Species oF Acer From THE Lower Litas, oF Witmcotre, WARWICKSHIRE. By Henry Woopwarp, LL.D., F.R.S., V.P.G.S., of the British Museum (Natural History). (PLATE XI.) HE genus Afger of Miinster was established in 1839, to contain some of the most beautiful forms of Prawn-like Crustacea found in the Solenhofen Limestone of Bavaria (see Beitriige, vol. ii. p. 64). Dr. Oppel, in his Paleontologische Mittheilungen (Stuttgart, 1862), p- 109, thus defines the genus : The inner antennz (antennules), with their long bifid filaments, start from three strong basal articulations, and attain in most specimens to twice the length of the whole body. The antennal scales are thin and very long. The basal joints of the inner antenne are finely serrated along their border. ‘They are much elongated, and project further in front of the head than the outer antenne, as is the case in the existing Shrimps. The rostrum of the cephalothorax forms a long and slender spine with several small tubercles along the sides. It may even attain the length of the cephalothorax. These characteristics may not however all be constant in the genus ger. The outer maxillipeds or jaw-feet are of great length, and are furnished on either side with a row of slender moveable spines of considerable length. A very small spine usually springs from the base of each of the larger spines. The first three pairs of true thoracic feet are chelate at their extremities, and are also. partially covered with similar moveable spines. The first pair of chelipeds are the smallest, the second are some- what larger, whilst the third pair are always the largest. The fourth and fifth pairs of legs are monodactylous, and are generally very long and slender, but vary in different species. The surface of the whole of the integument is thin, but very finely granulated, even the caudal plates displaying this character. The form of the abdomen furnishes no marked peculiarities. The false abdominal feet with their basal articulations are frequently preserved. The outer caudal lamella are divided diagonally by a line of articulation near their distal extremity. Through the kindness of the Rev. P. B. Brodie, M.A., F.G.S., DECADE III.—VOL. V.—NO. IX. 25 386 Dr. H. Woodward—On a New Lias Crustacean. Rural Dean, and Vicar of Rowington, near Warwick, I have received a block of Lower Lias Limestone from the “ Insect-bed” (Ammonites planorbis-zone) at Wilmcote, containing a very well-preserved specimen of a Macrourous-Decapod Crustacean referable to the genus ger of Miinster. The specimen was obtained by the Rev. H. E. Lowe, M.A., residing at Wilmcote, who procured it from one of the quarrymen, and afterwards generously presented it to Mr. Brodie. Like similar fine-grained fissile limestones, such, for instance, as the Lithographic Stone of Solenbofen in Bavaria, these Lias beds divide up into more or less numerous layers, the fossil-remains being exposed as impressions and counterparts, upon the corresponding surfaces of the slabs when split along their lamine. In this instance, however, only the single slab containing one side of the organism, has been preserved, so that some parts of the surface of the body- segments and appendages, which had adhered to the counterpart, have been lost with it. The specimen, which is of the bigness of an ordinary-sized prawn —the body being 44 inches in length—is lying upon its left size. Its rostrum, which is not serrated, is exceedingly slender, and as long as the entire carapace. The right ophthalmite, and its peduncle, are very well preserved. Only traces of the first or inner pair of antennze can be detected ; but the outer antenne, with their long multiarticulate filaments, can readily be observed, together with the prominent spine near the base of the same that gives support to the long oval antennal scale, the impression of which can also be clearly made out. Next is seen a pair of extremely long spinigerous maxillipeds, with simple non-chelate extremities, their four distal joints armed with two rows of long, sharp, and slender articulated spines arranged at regular distances apart along each border. Next follows the first pair of walking-legs, which are slender and shorter than the maxillipeds, and are provided with chelate termina- tions. The second pair of legs are also chelate, and similar to the first. The third pair are broken off near the body. The fourth and fifth pairs of limbs are long and very slender, and have likewise simple monodactylous terminations. The carapace is twice as long as it is deep, its surface smooth, and, where preserved, of a rich brown colour. Just over the branchial region the carapace (branchiostegite) is wanting and we see exposed the vertical ridges of the calcified endophragmal system, consisting of the infoldings of the lateral walls of the thorax, to which the legs are articulated, and which give attachment to the muscles of the limbs, and upon the outer face of which, but covered by the over- arching branchiostegite, the branchie or gills were situated. The specimen measures 106 millimétres in length by 40 mm. in depth, and displays the cephalothorax 53 mm. long by 20 mm. in depth, the rostrum being 24 mm. long, the pedunculated ophthal- mite 4mm. long. Behind the cephalothorax are seen the six abdominal segments of nearly uniform size, the last supporting the ‘telson’ or terminal T. C. Russell—The Jordan-Arabah and the Dead Sea. 387 joint, which is slender and pointed, and has the caudal lamelle of the 6th segment lying close beside it; the outer one of which is marked by a transverse articulation near its lower extremity. The false abdominal feet, with their basal joints and their bifid multiarticu- late appendages (exopodite and endopodite), are also clearly seen. In 1866 I described a new species of Alger from the Lias of Lyme Regis, Dorset (see Guot. Mac. 1866, p. 10, Pl. I.). This specimen, which I named Ager Marderi, is much larger, and alto- gether more robust, with shorter and stouter limbs than that now under consideration. Mr. Brodie’s specimen is not only smaller, but the limbs are much longer and more delicately slender.’ ’ Having many beautiful examples of these elegant Crustaceans from Solenhofen now before me (part of the grand collection formed by Dr. Haberlein, and purchased of him in 1863 for the British Museum), I have been able to study and compare this fossil from Wilmcote with these, and also with that from Lyme Regis referred to above, and I am of opinion that it is specifically distinct from all these, although the species have, as a whole, a well-marked generic facies. I propose, therefore, to name this form ger brodiei, in honour of my valued geological friend, the Rev. P. B. Brodie, whose labours in the Liassic beds of Warwickshire and elsewhere, extending over half a century, have resulted in a large accession of interesting and beautiful Arthropoda to the Liassic Fauna of Britain. II.—Tue Jorpan-AraBan Depression AND THE Drap Sma. By Israzt C. Russet, Of the United States Geological Survey (Appalachian Division of Geology), Department of the Interior, Washington, D.C., U.S.A. (Concluded from the August Number, p. 344.) Lacustrine History of the Dead Sea Basin. HE occurrence of numerous terraces on the mountain slopes over- looking the Dead Sea has been reported by several observers, but no accurate measurements of their elevations or definite correlation of the terraces on the opposite slopes of the depression, seem to have been attempted. In the central part of the Wady Arabah on the west flank of the promontory known as Samrat el Fedan, a terrace, or perhaps more properly a gravel bar, has been observed by Hull? at an elevation of about 1300 feet above the Dead Sea. This is apparently a definite record of the surface level of the Dead Sea during a former period. On the sides of the Jordan valley the terraces range in height from a few feet to 750 feet above the river. The measurements reported show great variation due princi- pally to an inclination of the surfaces of the terraces, towards the centre of the valley, but indicating also that they are not horizontal in the direction of drainage. The terraces of the Jordan valley, although 1 Tn describing the Lyme Regis fossil, I erroneously spoke of the long spinigerous maxillipeds as the first pair of thoracic legs. 2 Geol. and Geog. of Arabia Petrea, Palestine, etc., page 87. 388 TI. O. Russell—The Jordan-Arabah and the Dead Sea. usually referred to as lake terraces, seem to admit of another inter- pretation. The Dead Sea basin has been deeply filled, especially in its northern and southern portions, by lacustrine sediments, supplemented by gravel and sand washed from tributary valleys and neighbouring alluvial slopes. It seems probable that these deposits filled the basin from side to side in the Jordan valley and in the Wady Arabah, but not so completely as to form a level floor throughout. When the waters of the ancient lake fell to a lower level than the surface of the sedi- ments in question, the Jordan flowing from the north and the Jeib from the south, toward the Dead Sea, cut channels in the previously formed deposits. Pauses in the lowering of the lake surface would establish a base level of erosion for the inflowing streams, thus allow- ing them to widen their channels, so that when another lowering of the lake occurred and the streams re-commenced the excavation of their channels, a terrace would be left on the sides of their valleys. These terraces would slope with the grade of the streams which formed them, and on reaching the Dead Sea basin, would unite with the horizontal terraces formed by the waters of the inclosed sea. This interpretation of the history of the terraces of the Jordan valley is strengthened by the following observation recorded by Hull in the narrative of his journey of exploration.’ ‘All these terraces (along the Jordan near Jericho), excepting perhaps the upper, have doubly sloping surfaces, both toward the centre of the valley and toward the Salt Sea. The upper terrace only slopes toward the centre of the valley, as its upper surface corresponds almost exactly with the terrace of Jebel Usdum, and the other old sea margins, near the southern end of The Ghér.” Sections of the material filling the Wady Arabah near the steep descent to the plain of the Dead Sea show fine lacustrine sediment at the base, passing into sand and gravel in the upper portion. The surface of this deposit rises when followed southward or up the valley, but breaks off abruptly, as mentioned above, in a steep escarpment about six hundred feet high at the north, facing the depression now holding the Dead Sea. The structure of this deposit so far as known, as well as its topographic form, suggests the pro- bability that it is of the nature of a delta, the steep lakeward scarp of which has been cut away by the waves and currents washing its base. A similar interpretation will apparently apply in many ways to the facts reported concerning the material filling the Jordan valley. Q.J.G.S. 1881, vol. xxvii. ‘ On the Constitution of Grits and Sandstones,”’ pl. i. figs. 1, 2, 3, 5. DECADE III.—vVoOL. V.—NO. IX. 27 418 Miss C. A. Raisin—Rocks from Somali Land. many obscure Foraminifera, such as Amphistegina (?); and there are also remains of Polyzoa (?). (3.) Limestone from Hilo. The slides of this rock exhibit :— Fragments of Lamellibranch shells, of Polyzoa, of (?) a plate of an Kchinoderm, and Gorgonia-like spicules. Foraminifera :—Lagena, Globigerina, Textularia (common), Pla- norbulina, Rotalia, Miliola, sections of specimens having affinities (?) with Miliolina, and rather Trochammina-like in form. The general facies of this fauna is characteristic of late Cretaceous and of Tertiary formations, but if the forms doubtfully identified as Amphistegina belong to that genus, its occurrence, fairly abundant, would rather suggest that the limestone may be of Miocene age, and thus possibly contemporaneous with that of Socotra.? From certain miscellaneous specimens, we may infer that flint and chert, containing traces of organic remains, were formed in connection with the calcareous rocks. The deposition of a ferruginous material is everywhere emphasized in sands and grits, in the coating of larger pebbles, and in irony concretions, recalling the description of a neighbouring locality where the ground was said to look as if strewn with iron slag.’ The district, illustrated by these rock fragments, is evidently one in which the foundations of the hills are composed of gneisses and schists, which are laid bare in the valleys, possibly in association with granite. Among these rocks, there are evidences of the action of pressure, and thus, in the higher ranges further inland, this gneissic series may be raised to a greater elevation and may form a larger part of the mass, as in the place where Sir F. Burton describes walls of rock full of glittering mica.* The central massif would be concealed beneath gently stratified sedimentary beds. Some of these are grits and sandstones, which mark the results of a denudation of older crystalline rocks, others are limestones, sometimes Foraminiferal. The crystalline series is found to the eastward, as shown in the sections from Somali Land published by Dr. A. T. de Rochebrune * from notes brought back by M. Révoil, and still further eastward in the Island of Socotra.’ Northward, similar rocks occur in Abyssinia ° and Egypt, and in the peninsula of Sinai. Sandstones and limestones have a similarly wide extension, although further evidence is needed to fix the exact age and correlation of these formations in the Hilo district. Some of the sandstones seem, lithologically, rather like those, which Dr. Rochebrune compares with the older sands of Nubia and of Adigrat; the overlying calcareo-argillaceous rocks he identifies by their fossils as of Neocomian age. Thus the rocks, described in this note, vary in some details from those of neighbouring localities, yet bear out, on the whole, the inference of Professor Bonney as to the wide extension which has characterized former geological con- ditions in North-eastern Africa. 1 Phil. Trans. 1883. 2 «First Footsteps in Africa,” p. 391. 3 « First Footsteps in Africa,” p. 396. * Faune et Flore des Pays Comalis, G. Révoil, 1882 (Observ. Géol. Dr, A. T. de Rochebrune). 5 Phil. Trans. 1888. ° Geology and Zoology of Abyssinia, W. T. Blanford. Dr. H. Woodward—On a Carboniferous Eurypterus. 419 VII.—Norr on Huryprervs FROM THE CARBONIFEROUS. By Henry Woopwarp, LL.D., F.R.S., V.P.G.S., of the British Museum (Natural History). N the Grotogrcan Magazine for November last (Decade III. Vol. IV. p. 481, Pl. XIII.) I gave a brief description of a new species of Hurypterus from the Lower Carboniferous Shales, Eskdale, Scotland, which I named Eurypterus scabrosus. I referred to other Carboniferous forms, and briefly mentioned one from the Lower productive Coal-measures, Darlington, Pennsylvania, U.S.A., figured as a woodcut only in the American Phil. Soc. Proc. vol. xix. p. 152, 1881. I was not aware at that time that my friend Professor James Hall, of Albany, had printed a “ Note on the Lurypteride of the Devonian and Carboniferous Formations of Pennsylvania.” [Extracted from Report of Progress PPP, Second Geological Survey of Pennsylvania. Svo. with six plates, Harrisburg, 1884; printed in advance. | Having, through the kindness of the author, been favoured with a copy of this memoir, I hasten to remedy the omission in my paper referred to above, and to state that Professor James Hall has fully described and figured this Coal-Measure Eurypterus from Darlington under the name of H. Mansfieldi. Both in the form of its appendages and its size EH. scabrosus is quite distinct from Hall’s £. Mansfieldi, the latter being not more than nine inches in length, whereas the former measured, when perfect, probably not less than 20 inches. JH. scabrosus was, moreover, furnished with long and slender bluntly- spinose appendages, but in EH. Mansfieldi the palpi terminated in sharp recurved spines, closely resembling the earlier U. Silurian forms both in its palpi and swimming-feet. Prof. James Hall devotes 24 figures to the illustration of this species ; he also figures and describes three others (H. potens, E. stylus, and E. Pennsylvanicus) from the same locality and formation as HE. Mansfieldi. EE. stylus is a much smaller form, only about half the length of the former. E. Pennsylvanicus is only known by a detached carapace, and H. potens by some detached portions. Professor James Hall also adds an important note on Eurypterus (Anthraconectes) Mazonensis, Meek and Worthen, from the Coal-measures of Grundy Co., Illinois (see Amer. Journ. Sci. vol. 46, p. 21, 1868: also Geol. Surv. of Illinois, vol. iii. (Geology and Paleontology), 1868, p- 544, woodcut figure). This, as Hall very correctly points out, is no doubt a true Hurypterus, and the slight differences pointed out by Messrs. Meek and Worthen do not seem to justify the placing it in a distinct genus. Prof. Hall figures a second specimen from Mazon Creek, which he believes to be the actual counterpart of Meek and Worthen’s specimen, and points out how closely it agrees in many respects with HE. Mansfieldi, the differences being really only of specific value. The same author also figures and describes a very complete but headless body of a Eurypterus from the Chemung group (Upper Devonian) of Warren, Pennsylvania (plate iii. p. 80, op. cit.), which 420 Dr. H. Woodward—On a Carboniferous Eurypterus. he names EH. Beecheri.' From the presence of parts of two long slender, ridged, non-spinose appendages associated with the body in the position which would have been occupied by the swimming-feet, J am led to surmise that this may possibly prove to belong to the genus Stylonurus ; but I offer this suggestion with extreme caution and reserve, well knowing the great care and vast experience of Prof. James Hall in dealing with this group of ancient Merostomatous Crustacea. Body-segments of Eurypterus Wilsont, H.W. (natural size), Coal-measures, Radstock, Somerset. Before concluding this note, I desire to call attention to a very interesting discovery made by Mr. Edward Wilson, F.G.S., of the Bristol Museum, of a part of the body of a Eurypterus (see woodcut) from the true Coal-measures at Ludlow’s Pit, Radstock, Somerset. The specimen consists of the first six body-segments only, following immediately behind the head: they measure together 533 millimétres in length by 52 mm. in greatest breadth. The first segment, as is constantly the case, is shorter than any of the others, being only 4; mm. deep; the 2nd is 8 mm.; the 3rd 11 mm.; the 4th, dth, and 6th are each 10 mm. deep. The first segment is nearly straight and 42+ mm. broad; the segments gradually become more arched, and increase in breadth slightly to the 4th, which is 52 mm. broad; contracting slightly to the 6th segment, which is 474 mm. broad. The Ist, 2nd, and 8rd segments have their lateral borders nearly straight, but the 4th, 5th, and 6th are rather more expanded and the posterior angles are produced and rather more pointed. The surface of each segment is marked by squame which are extremely numerous and very minute along the anterior border of each segment, but near See also Natural History of New York, Paleontology, vol. vii., by James Hall (with supplement to vol. v. part ii.), 1888, pl. xxvii. fig. 5, p. 156 (just received). Notices of Memoirs—Cambrian of Baltic Provinces. 421 the centre and at the lateral angles these scale-markings become much larger, more acutely pointed in shape, and more irregularly distributed. These scale-markings agree exactly with those of Hurypterus Mansfieldi (Hall), as represented by Prof. Hall on an enlarged scale (see plate v. fig. 6, op. cit. p. 88), but the margins of the segments of the Radstock specimen are hardly so pointed at their latero- posterior angles as the American species above quoted. The pro- portions are about equal to the largest example recorded by Prof. Hall. In the absence of the rest of the organism, it would be premature to speak confidently ; but, as it will probably prove to be a distinct British species, but near to H. Mansfieldi of Hall, I would propose to name it provisionally Hurypterus Wilsoni, after its discoverer. NOTICES OF MEHMOTRS. CamBRIAN Fauna IN ESTLAND. UEBER EINE NEUENTDECKTE UNTERCAMBRISCHE F'AuNA IN ESTLAND. Von F.Scumipr. Mit zwei Tafeln. (Mem. de l’Acad. des Sciences St.-Pétersbourg, vii® série, tome 36, 1888, pp. 1-28, pls. i. ii.) ITHERTO the Cambrian strata of the Russian Baltic provinces have proved so exceedingly poor in fossils, that it has not been possible to make a satisfactory comparison between them and the relative beds in Sweden and elsewhere. Below the Dictyonema shales, which are analogous to the beds of the same name in Norway and Sweden, there occurs the Unguliten or Obolus sandstones ; and beneath these are beds of blue clay with subordinate layers of sand- stone, which rest upon Finland granite, and have been proved by borings to reach 600 feet in thickness. The upper portions of the blue clay series in Estland were regarded by Linnarsson in 1872 as equivalent to the Hophyton sandstone of Sweden, and the main mass of the Unguliten sandstone as representing the Fucoid sandstone of the same country; but at that time no fossils were known which could substantiate these views. Lately, however, thanks to the persevering efforts of M. Mickwitz, an engineer of Reval, the frag- mentary remains of a characteristic fauna have been discovered in the upper beds of the blue clay series at Reval and the neighbour- hood, which fully confirm Linnarsson’s opinions. The fossils which have been carefully described and figured by F. Schmidt in the present paper are Olenellus Mickwitzi, n.sp., Scenella discinoides, n.sp., S.? tuberculata, n.sp., Mickwitizia (Obolus?) monilifera, Linnars. sp-, Obolella (?) sp., Discina (?) sp., Volborthella tenuis, n. gen. et sp., Platysolenites antiquissimus, Kichw. sp., Medusites Lindstreemi, Linuars. sp., Primitia?, Cruziana, and Frena tenella, Linnars. The Olenellus Mickwitzi comes in at a lower stage than the O. Kjerwfi, and is thus the oldest Trilobite known in Europe. Its occurrence at this horizon confirms the views of Linnarsson, Holm, and Brogger, that the Olenellus zone is distinctly older than that of Paradouides. 422 Reviews—C. Brongniart—On Pleuracanthus. The following table is given by the author to show the equivalents of the Cambrian strata of the Baltic provinces with those of Norway and Sweden. Batic. SWEDEN. Norway. Dietyonema-shale Dictyonema-shale Dictyonema-shale.—2e Unguliten-sand 2d 2 Olenus-zone Olenus-zone an 2a Paradoxides-zone Paradoxides-zone id Olenellus-zone. Zone of O. Kjerulfi Zone of O. Kjerulfi.—1b Fucoid-sand Fucoid-sandstone. Zone of Olen. Mickwitzi Eophyton-sandstone Ta Blue Clay Sparagmit-stage | Lower Sandstone Fr. Schmidt thinks that the Baltic Olenellus zone is equivalent to the lower part of the St. John’s group in North America, and to the lowest stages of our Harlech and Longmynd groups, in which no Trilobites have as yet been found, whilst the Dictyonema shales and the Unguliten sand may be paralleled with the Lingula Flags. dey Jet WS JB OS We Se I.—M. Cuaritres Broneniart on PLevRACANTHUS.! HE precise characters of the extinct cartilaginous fishes, whose detached teeth and spines have long been known under provisional names, are now becoming gradually revealed through the progress of research; and no more interesting and important discovery has been made of late than that of the complete trunk of Pleuracanthus, described last April by M. Charles Brongniart, of the Paris Museum of Natural History. Through the kindness of M. Brongniart we are enabled to present the accompanying woodcut, which is a restoration of the skeleton of the fish, based upon no less than twenty-three examples of a new species (Plewracanthus Gaudryi), from the Coal-measures of Commentry, Allier, France. The known individuals vary in length from 0:45 m. to 1 m., pre- sumably owing only to their differences in age; the skeleton is always well displayed, being calcified as in Selachians, while the skin is destitute of shagreen. The body is elongate in form, and the snout obtuse. The notochord is persistent, and the bases of the neural and hemal arches expanded; the slender neural spines bifurcate distally in the greater part of the abdominal, and the anterior half of the caudal, region. ‘The pectoral fin, as already pointed out by Goldfuss and Anton Fritsch, is a biserial archiptery- gium; and each of the pelvic fins in the male is provided with a robust clasper, as in Chimeeroids and Selachians. The barbed spine is placed upon the head, and forms the anterior border of a small “cephalic” fin; and a long dorsal fin commences almost ' “Sur un nouveau Poisson fossile du terrain houiller de Commentry (Allier),”’ Comptes Rendus, April 23rd, 1888. 423 Reviews—C. Brongniart—On Pleuracanthus. TREN ‘HONVU ‘ATITTY ‘AULNAWWOD ‘SHUASVAN-TIVOD FHL WOU ‘yavlusuolg “Yhupnpyy snypunovanag f0 wo1jnsojsay LAVA AVANAASS ‘ep TaIqog z JAvlusuorg 424 Reviews—C. Brongniart—On Pleuracanthus. immediately behind, sharply separated from the upper half of the elongated diphycercal caudal, to the commencement of which. it extends. But most singular and novel are the two small repre- sentatives of the anal fin, which are “placed one behind the other and have the appearance of true limbs. Narrow at their base, they enlarge mesially, and then become contracted. Their skeletal framework is almost identical. The hemapophyses supporting them are truncated instead of ending in a point. The first two hemapophyses bear very slender interspinous elements which are in connection each with a fin-ray. The third is larger, broad at its extremities, supporting distally a shorter broader ossicle. From this are detached, above a ray, and below two short ossicles, of which the first supports an ossicle and fin-ray, and the second two ossicles and two fin-rays. We find nothing comparable in nature, fossil or recent.” It may also be added that Dr. Anton Fritsch will be able to make known interesting confirmatory—perhaps supplementary—evidence upon these points, when the Bohemian Pleuracanths are described, the writer of the present notice having been favoured with an inspection of beautiful examples in Prague. The completed memoir on this important discovery has yet to appear, but M. Brongniart remarks, at the conclusion of the pre- liminary note, that, as the result of his studies, Plewracanthus must be regarded as representing at least a distinct order, perhaps a sub-class, the * Pleuracanthides,”—“ a group ancestral to, and connecting, the Dog-fishes, Cestracionts, Rays, Chimeras, Sturgeons, and Ceratodus.” It is to be hoped, however, that before proposing any new term, the author will consider in more detail the conclusions of previous workers in the same direction. Prof. Cope has already placed a member of the group in a distinct order, the “Ichthyotomi,” equivalent in value to the order of Selachii; and although Mr. Garman remarks, apparently with much reason, that the definition originally proposed (relating to so-called distinct traces of ossification in the chondrocranium) is very doubtfully accurate, all recent researches have tended towards as complete an isolation of the Pleuracanthus-like fishes as now seems inevitable. Dr. Traquair’s description of the genus Chondrenchelys, with the appearance of a splint-like bone (? parasphenoid) upon the chondrocranium, and with complete broad vertebral rings in the caudal region, will likewise require consideration ; and the same author’s discovery of a uniserial archipterygial pectoral fin in Cladodus seems to the writer of this notice to place that much-discussed genus also in the great Pleuracanth order. The archipterygial character of the pectoral fin will certainly become one point in the broad diagnosis of the group, although, it must be admitted, a few Selachii (e.g. Squatina) exhibit some faint approach to that condition ; and it cannot be said that the torm of the teeth will count of much value, for the depressed and posteriorly expanded character of the base in the teeth of Cladodus is precisely paralleled in some Notidanidee and undoubted Hybodonts, which are true Selachii. It has hitherto been too much the custom to regard every ancient fish, destitute of membrane bones and Reviews—Dr. C. A. White’s Fossils of Brazil. 425 possessing dermal structures of vascular dentine, as a member of the Selachian order ; and the results of M. Brongniart’s researches upon the exquisite examples of Plewracanthus Gaudryi will be anxiously awaited, on account of the valuable new light they are destined to shed upon such questions. A. Suita Woopwarpb. IJ.—Contrisvutions To THE PaLmontoLocy or BraziL; comprising Descriptions of Cretaceous Invertebrate Fossils, mainly from the Provinces of Sergipe, Pernambuco, Para, and Bahia. By Cuartes A. Wuitr. With Portuguese Translation by OrvILLE A. Dersy. 4to. pp. 2738, and 28 Plates. (Extracted from vol. vii. of Archivos do Museo Nacional do Rio de Janeiro.) (F\HE fossils described by Dr. White were collected some years since by the Brazilian Geological Survey under the direction of the late Professor Hartt, from low-lying rocks of sandstone, limestone, and shale, occurring in several disconnected areas bordering the Brazilian coast, from the mouth of the Amazon southwards. These rock-basins are open towards the sea, but land- wards are bounded by higher ridges of crystalline, and probably Paleozoic, strata. Some of the deposits in the neighbourhood of Bahia are of freshwater origin. Both marine and freshwater beds are referred by Dr. White to a Cretaceous age, since the majority of the typical fossils from them are characteristic of this period, and some are identical with undisputed Cretaceous fossils of other regions. But with these fossils occur others of a distinct Jurassic aspect, though not specifically identical with any known Jurassic Species, and, again, these are mingled with Gasteropods belonging to Fusus, Murex, Phorus, etc., which, if occurring alone, would have been referred to the Tertiary period. Judging by the Mollusca, the author finds this Brazilian fauna more nearly related to the Cretaceous fauna of Southern India than to any other yet known, and next after this, it approaches the fauna of the Gosau beds in the Tyrol. The freshwater Mollusca from the Bahia beds are likewise peculiar, since the species (of which 11 are described) belong to recent types. There are 82 species of Conchifera (Lamellibranchiata) described, most of them new; the best represented families are the Ostreeide, Limide, Pteriide, Arcide, Crassatellide, Cardiide, and Anatinidee. Of Gasteropoda, 91 species have been determined, 77 of which are regarded as new; the Naticide, Cerithiidw, and Fasciolariide are the most numerously represented families. A single new species of Polyzoa, Lunulites pileolus, closely resembles the L. annulata, Stol., from the Cretaceous of Southern India. There are 13 species of Cephalopoda, which, with the exception of a form of Helicoceras and one of Nautilus, belong to the Ammonitide. Fourteen species of Echinoderms are described, with one exception they are regarded as new. All the new species, and some others as well, are carefully illustrated in the accompanying plates, and a good index is 426 Reviews—Dr. Waagen’s Salt-range Fossils. appended. It may also be mentioned that the author gives, at the beginning of the work, a bibliographical list of publications on the invertebrate Mesozoic fossils of South America. The list only includes 24 titles, and thus indicates the slight amount of work which has hitherto been done on this group of fossils within the bounds of this continent. We note one omission; that of a short paper by Prof. E. Forbes on the Secondary fossil shells from South America, given as an appendix to Part II. of Darwin’s “ Geological Observations.” III.—ALicemetne Gronoci, von Dr. Karu v. Frirscu, Professor an der Universitit in Halle. Mit 102 Abbildungen. Biblio- thek Geographischer Handbiicher. Herausgegeben von Prof. ae Frreprich Rarzen. (8vo. pp. 500.) Stuttgart, Engelhorn, 1888. N Germany, not less than in England, new manuals of Geology, and new editions of old ones, appear with a frequency which indicates a considerable amount of interest, both on the part of students and of the public generally in the science of which they treat. The present volume by Prof. von Fritsch is brought out as one of a series of Geographical handbooks, and there can be no doubt of the importance of a thorough acquaintance with the facts and principles of geology to any one who aims ata real knowledge of geography. This book seems to be well adapted for its purpose ; though necessarily it covers the same ground as other manuals of the science, the subject is treated from an independent point of view, and’ the author may justly claim that it is not a mere compilation, but has been based on his own study and observation of the facts. The following is the arrangement adopted in the work :— I. Geophysiography ; II. Geotectonic or Stratigraphy; III. Geo- chemie or Chemical Geology, including Petrography and Lithology ; IV. Geomechanic or Physical Geology; and V. Geogenie or His- torical Geology. The facts and deductions relating to each of these divisions are stated very clearly and concisely, and the work may be commended, not merely to beginners, but to students of Geology generally. G. J. H TV.—Sart-Ranee Fossius. By Wititram Waacen, Ph.D., F.G.S. I. Productus-Limestone Fossils: 6. Coelenterata, Memoirs of the Geological Survey of India, 1886, pp. 885-924, plates xcvi1.- CXVi. N this elaborate memoir the Corals of the Carboniferous Lime- stone of the Salt-Range of the Punjab are described in detail, and illustrated on a scale which might give rise to the envy of non-official paleontologists, who have to be content with figures of much humbler proportions. These Corals are, for the most part, of the same general characters as those of the Devonian and Carbon- iferous strata of this country and North America. They belong to the genera Arepora, Pachypora, Michelinia, Monotrypa, Orbipora, Geinitzella, Stenopora, Lonsdaleia, Ampleaus, Hexagonella, Dybow- Correspondence—Dr. A. Irving. 427 skiella, and Fistulipora. Of these, Geinitzella, Hexagonella, and Dybowskiella are proposed as new, but their characters are so similar to those of Stenopora, Evactinopora, and Fistulipora respectively, that the author might well have spared the introduction of the new names. A very important feature in the description of these Corals is the way in which their minute structures have been investigated by means of microscopic sections, of which several hundreds were prepared by Mr. Wentzel, the colleague of Prof. Waagen in the authorship of this memoir. A comparison of the beautiful figures given of these sections, with those of nearly allied forms which have appeared in the papers of Prof. Nicholson and Mr. Foord, fully shows the value and absolute necessity of basing the determination of these and other Corals on their minute structural characters. In the interpretation of some of these minute structures, the authors of this memoir differ considerably from Prof. Nicholson; but we are inclined to think that, as regards the nature of the wall in the axial corallites, the view of Prof. Nicholson, that it is really double, better accords with the facts, than the explanation that it is single, and that fracture really takes place between it and the subsequently deposited layers of stereoplasm. Further, the evidence seems insufficient to establish the statement that the spinous structures in many of the Monticuliporide, the Acanthopores of Nicholson, are merely the young stages of the ordinary corallites. Other points, on which somewhat dogmatic opinions are given, are likewise open to criticism ; but we must content ourselves with an expression of satisfaction that these organisms have been so thoroughly and carefully investigated and described; so that this memoir is a refreshing contrast to some of the earlier publications of the Indian Survey, in which the superficial features of the Corals merely have been noticed. A tabular statement of the species described in the memoir would have increased its value and convenience for reference. Cade Jal; CORRESPONDENCE. ————— THE ATMOSPHERE OF THE CARBONIFEROUS PERIOD. Srr,—May I be permitted one word on a question which has been raised as to the greater prevalence of carbonic acid in the atmosphere of this earth in the Carboniferous Period than at later periods, if only to suggest that Prof. Prestwich and his critic seem to be arguing at cross-purposes? There is no reason why both statements should not be true. The real question would then be, as to what would constitute “an excess of carbonic acid.” There is some confusion of thought as regards such two essentially different physiological functions of plant-life and growth as respiration and assimilation of carbon. This is hardly excusable when we need go no farther than the most trustworthy elementary books (such as those in the London series), to be informed of the essential difference of these two processes, and of necessity of free oxygen for the activity of proto- plasm in the plant and animal alike. On general grounds therefore 428 Obituary— Prof. Henry Carvill Lewis. we should expect that a moderate increase (beyond the mere four parts in 10,000 of our present atmosphere) of the food-stuff (carbonic acid) of plants would be favourable to more rapid production of vegetable tissue ; and on the same grounds we should equally expect that such an increase of the same gas, as to practically asphyxiate plants, would be fatal to them. But between the two limits there is ample room for Prof. Prestwich’s hypothesis, which is probably well founded. Why not experiment on the question? It is easy enough. Sachs (Lehrb. d. Botanik, p. 692) states that ‘experiments on plants (Vegetationsversuche) show that growth and the changes of material necessarily associated therewith only take place in the tissues (of plants) so long as free oxygen has access to them: in the absence of free oxygen (in einer saiierstofffreien Atmosphiire) no growth takes place; and if plants remain a longer time in such an atmosphere they die.” If, however, the percentage of carbonic acid in the present atmosphere were multiplied, say 100-fold, its volume would still be less than one-fifth that of the free oxygen present. This we should scarcely expect to reach the asphyxiation-proportion for plants. The above quotation is from the Leipzig edition (1874) of Sachs’ great work. It is probable that in the recent new edition much fuller information is to be found. WeLuincton CoLLecE, Berks. A. Irvine. 4th May, 1888. (GESPEAR OWA EL Na PROF. HENRY CARVIEL (CEWIS,” MEAs iE iGuse Born NovemsBer 167TH, 1853; Dizp Jury 21st, 1888. Amonest the many and varied ties which serve to bind America and Iingland together in friendly union, there are probably none more sincere and reciprocal than those which subsist between the scientific men of the two countries. As Englishmen we take the warmest interest in the grand development of that wonderful country “on the other side,” and the hearty reception given to our American cousins here is returned with equal or even greater warmth by them, whenever we visit the New World. It is doubtless owing to their greater energy and enterprise that Americans are by far the more frequent visitors to our shores than are we to theirs. This is no doubt largely due to the historical attractions which an old country always offers to a new one, and also the desire to compare our scientific work and institutions with their own. No one amongst the many young scientific Americans of note has more earnestly cultivated English and European methods of research, or has worked with greater enthusiasm to carry his geological investigations from North America into Britain, than the subject of this brief memoir, Professor Carvill Lewis. H. C. Lewis was Obituary—Prof. Henry Carvill Lewis. 429 born in Philadelphia, November 16th, 1853, being the son of Mr. F. Mortimer Lewis and Emma Hulme (Carvill) Lewis, of that city. At the age of 20 he graduated B.A. with first honours in Classics at the University of Pennsylvania, taking his M.A. degree in 1876. He took a post-graduate course of three years in Natural Science, and between 1879 and 1884 he served as a volunteer on the staff of the Geological Survey of Pennsylvania; investigating at first the surface-geology of Southern Pennsylvania, and afterwards the Glacial phenomena of the Northern part of that State. Here he succesfully traced the great terminal moraine of the North American Ice-sheet from New Jersey to the frontier of Ohio. During this period he contributed a number of papers to the Academy of Natural Sciences of Philadelphia upon the mineralogy and geology of Pennsylvania. In 1880 he was elected Professor of Mineralogy in the Academy of Natural Sciences, Philadelphia, and in 1883 he was appointed Professor of Geology in Haverford College, Pennsylvania, U.S. In 1882 Prof. Carvill Lewis married Miss Julia C. Foulke, daughter of the late Mr. W. Parker Foulke of Philadelphia, a man of varied attainments and wide scientific interests. Between 1885 and 1888 he was engaged in studies and original investigations in Kurope; the winters being spent in Heidelberg, where he worked at microscopic petrology and crystallography, under the guidance of Prof. Rosenbusch, and the summers in the field tracing out the difficult and complex problems connected with the Glacial ‘Epoch i in Great Britain and on the Continent. Here he had completed a map of the ancient glaciers and ice- sheets of England, Wales and Ireland, which was exhibited and discussed at the British Association, Birmingham, 1886; Manchester, 1887 ; and elsewhere. He had also commenced similar studies in Switzerland and North Germany. ‘These, however, were interrupted by a visit to America, where he contracted typhoid fever, which developed in a sudden and alarming manner immediately on his return to England, and terminated fatally on July 21st, at Manchester. Prof. Carvill Lewis was a Fellow of the Geological Society of London; of the Geological Society of Germany; a Member of the American Philosophical Society ; of the Academy of Natural Sciences of Philadelphia; the Franklin Institute; the American Association ; a Corresponding Member of the British Association ; and a Member of the Geological Society of Liverpool. It is always sad to see a bright young life suddenly cut short in early manhood, but it is more especially so when, as in the case of . Prof. Carvill Lewis, such good work had been already done, and we had abundant promise of a splendid future scientific career. Over and above all this Prof. Lewis had such a happy, bright and genial manner, that he readily won for himself the warm regard of a very wide circle of friends, whilst among men of science he seemed to give sure promise of a long life of solid and valuable work. His loss will be keenly felt both in America and Europe, not only amongst geologists, but men of science generally. 430 Obituary—Prof. Henry Carvill Lewis. The following are amongst his more important papers :— “ On Philadelphite, a new Mineral Species.’’ (Proc. Acad. Nat. Sci. Philadelphia, 1879.) *‘The Optical HOOT! of some Micas.”’ (Proc. Acad. Nat. Sci. Philadelphia, 1880, PP. 244-251. ‘¢ Siderophyllite, a new Mineral.”” (Proc. Acad. Nat. Sci. Philadelphia, 1880, pp. 254-255.) ‘The Surface Geology of Philadelphia and its vicinity.” (Journ. Franklin Institute, 1883.) (Proc. Acad. Nat. Sci. Philadelphia, 1880, pp. 258-272.) “The Trenton Gravel and its relation to the Antiquity of Man.’”’ (Proc. Acad. Nat. Sci. Philadelphia, 1880, pp. 296-300.) ‘“‘The Iron-ores and Lignites of Montgomery Co. Valley.’? (Proc. Acad. Nat. Sci. Phila- delphia, 1880, pp. 282-201.) * A New ee Plant from the Trias.’’ (Proc. Acad. Nat. Sci. Philadelphia, 1880, pp. 203-204. *‘ Some Enclosures in Muscovite.”” (Proc. Acad. Nat. Sci. Philadelphia, 1882, pp. 311-315.) An American Locality for Helvite.” (Proc. Acad. Nat. Sci. Philadelphia, 1882, pp. 100- 102.) fF bee ana of Serpentine after Dolomite.’’ (Proc. Acad. Nat. Sci. Philadelphia, 1882, pp. 36-38. ‘The Great Terminal Moraine across Pennsylvania.’’? (Proc. Amer. Assoc. Adv. Sci. Montreal, 1882.—Sczenzce, 1883, vol. ii. pp. 163-167.) “*On a Supposed Human Implement from the Gravel at Philadelphia.”? (Proc. Acad. Nat. Sci. Philadelphia, 1883, pp. 40-43.) Fé Eee ent Variety of Limestone.”? (Proc. Acad. Nat. Sci. Philadelpia, 1884, pp. pp. 10-12. *‘Report on the Great Terminal Moraine across South-Eastern Pennsylvania and Western ; New York, 1884, pp. 299, maps, sections. and photograhs. *¢On Supposed Glaciation in Pennsylvania South of the Terminal Moraine.’’? (Amer. Journ. Sci. 1884, vol. xxxiii. pp. 276-288.) ‘‘ Erythrite, Genthite and Cuprite from near Philadelphia.’? (Proc. Acad. Nat. Sci. Phila- delphia, 1885, pp. 120-122.) “Marginal Kames.”’ (Proc. Acad. Nat. Sci. Philadelphia, 1885, pp. 157-173.) ** A Great nies Dyke across South-Eastern Pennsylvania.’’ (Proc, Am. Phil. Soc. 1885, pp. 38-456. Ke Concaesave Studies upon the Glaciation of North America, Great Britain, and Ireland.” (Gro. Maa. 1887, Ser. III. Vol. IV. pp. 28-32.) British Assoc. Reports, Birmingham, 1886. *‘ On a Diamantiferous Peridotite’’ and ‘‘ The Genesis of the Diamond.’’ (Brit. Assoc. Rep. Birmingham, 1886.) (Gror. Mac. Ser. III. Vol. IV. 1887, pp. 22-24.) (Sczexce, vol. viii. 1886, pp. 345-347-) | i i “The Terminal Moraines of the Great Glaciers of England.” (British Assoc. Reports, Manchester, 1887.) (Amer. Journal Science, 1887, ser. iii. vol. 34, p. 402.) ‘¢On some extra-Morainic Lakes in England, North America, and elsewhere during the Period of Maximum Glaciation, and on extra-Morainic Boulder-clay.’’ (British Assoc. Reports, Manchester, 1887.) (GEOL. Mac. 1887, p. 515.) *¢ On the Matrix of the Diamond.”’ (Brit. Assoc. Reports, Manchester, 1887.) (Grot. Mac. 1888, p. 129.) 6‘ The Terminal Moraine of the Irish Sea Glacier near Manchester.’’ (Brit. Assoc. Reports, Manchester, 1887.) Tar Terminal Moratnes oF THE Great Gracters or ENGLAND. Norr.—Mrs. Lewis desires to state that, after the meeting of the British Association at Manchester last year, Prof. Carvill Lewis set out in company with herself and Dr. H. W. Crosskey, of Birmingham, to visit and examine Frankley Hill, in Worcestershire, the only alleged deposit of glacial “Till” south of the great Moraine line which he had not seen prior to the Manchester meeting. Here an excavation was made, under Prof. Lewis’s superintendence, through the gravel to a depth of from eight to ten feet; thence the party traced the few detached Arenig boulders to the frontier of Wales. Prof. Carvill Lewis then said that for the first time in all his experience, both in the old and new world, he had found unmistake- able evidence of a glacier, between which and the Glacial Epoch there was as vast an interval of time as between that and the present day. It was the intention of the late Prof. Lewis to make a thorough re-examination of all England, lest a similar deposit elsewhere might have escaped his notice; but now that his labours have been so suddenly brought to a close, Mrs. Lewis thinks this statement should be put on record. —H.W. Obituary—Amos H. Worthen, of Illinois. 431 AMOS H. WORTHEN. PALHONTOLOGIST AND GEOLOGIST. Born Octoser 81st, 1812; Diep May 6ru, 1888. Amos H. Wortuen, a son of the late Thomas Worthen, was born at Bradford, Orange County, Vermont. He commenced life as a Schoolmaster in Harrison County, Kentucky, but in June, 1836, he removed to Warsaw, Illinois, where he spent the remainder of his life. While engaged in business, he became interested in the science of Geology, and made a large collection of fossils, and also of those remarkable geodes of the Keokuk limestone in that region, On the institution of the Geological Survey of Illinois in 1851, under Prof. J. G. Norwood, he was appointed his Assistant, which post he filled for four years. From 1855 to 1857 he was Assistant to Professors James Hall and J. D. Whitney on the Geological Survey of Iowa, and the volume published in 1858 owes much of its value and interest to the labours of Mr. Worthen. The many beautiful plates of this large volume are from drawings by Mr. F. B. Meek, who was afterwards associated with Mr. Worthen in the paleontology of his own Reports. In March, 1858, Mr. Worthen was appointed by the State to the charge of the Geological Survey of Illinois, which position he occupied till 1872, when he became Curator of the Illinois State Museum. The seven completed volumes of the Geology and Paleontology of Illinois form the best and most lasting monument to his memory. Mr. Worthen left an eighth volume in the press. Besides these voluminous reports, he issued a large coloured geological map of Illinois, and three volumes on the Economical Geology of the State. He was also the means of gathering for the State Museum one of the largest and best collections of fossils in the country. In the early part of the Survey Mr. Worthen encountered and overcame great opposition. His modesty and earnestness, high character and quiet dignity, gave him great influence, and the many difficulties disappeared before him. Although nearly 75 years of age at his death, he had not given up work; the preparation of the text and plates illustrating the Silurian Invertebrate fossils of Illinois, for the eighth volume, was occupying him, when a sudden attack of pneumonia brought all to an end.— Silliman’s American Journal, August, 1888. WIEEVAM SHEEEIERS BAILY. FL S.biG.o. MR lA. PALMONTOLOGIST AND GEOLOGIST. Born Juty 7, 1819; Drep Aveusr 6, 1888. We regret to announce the death, at Rathmines, near Dublin, of Mr. W. H. Baily, who, after a lingering illness, passed away on August 6, at the age of 69, The greater portion of his life was 432 Obituary— Wiiliam Hellier Baily. devoted to Paleontology, and most of the fossils which he described, and those which illustrated his works, were drawn on wood or stone by his skilful hand. Mr. Baily was born at Bristol on July 7th, 1819, and he inherited artistic talent, for both his grandfather and father, as well as his uncle, Edward Hodges Baily, R.A., were remarkable for their carving and sculpturing. He began his scientific career in 1837 as Assistant Curator in the Bristol Museum, resigning this post in 1844, when he was attached to the Geological Survey of Great Britain as Draughtsman. In the following year he was appointed to the staff as Assistant Geologist under Sir Henry De la Beche. His duties, however, were confined to the Museum work, and in 1854 he was styled Assistant Naturalist, serving for a time directly under Edward Forbes, and afterwards under Professor Huxley. In 1857 he was transferred to the Irish branch of the Geological Survey, as Acting Paleontologist, and he retained this post till the close of his life. In 1868 he received the additional appointment of Demonstrator in Paleontology to the Royal College of Science for Ireland. | Mr. Baily was the author of many papers on paleontological and kindred subjects, and his labours will be best shown by the list of his works, which amount to 43 in number. His most important private work was that published in parts from 1867 to 1875, being Figures of Characteristic British Fossils: with descriptive remarks. Unfortunately, the work did not sufficiently recompense the author from a pecuniary point of view, and after the first volume was published, completing the Paleozoic portion, it was abandoned. In 1867 he received the proceeds of the Wollaston Donation-fund, awarded by the Geological Society of London, in aid of this work. His official labours comprised Paleeontological Notes in the Ex- planatory Memoirs to the Maps of the Geological Survey of Ireland, and the list of these alone would be a lengthy one. Mr. Baily, like the late Prof. Morris, and Mr. J. W. Salter, with whom he was a contemporary and a fellow-worker, belonged to that small body of Geologists and Paleeontologists, now, alas! nearly all passed away, who possessed an extensive general knowledge both of _ rocks and fossils, and also the invaluable ability to draw, as well as to describe, what they saw and studied, whether in the field or in the cabinet. These men can never be replaced by our modern student-specialists. Personally Mr. Baily was of a genial disposition and his loss will long be felt by his friends and colleagues. Errata.—Please make the following corrections:—Gron. Mac. March No. p. 123, in footnote, line 2, for “Memoir” read ‘“ Meunier.” in May No. p. 240, line 33 from top of page, for the work which Mr. Lee has actually done—read “the work which we see actually done.” —In August Number, p. 382, line 8 from bottom, for lavas read laws.—Hpir. Grou. Mac. ~ Geol Mag. 1888. Decade III Vol V.PLXIL Yes GM Woodward, del et ith West Newman & C?imp: Bryon antiquus, Broderwp, sp. Li, Los. Lyme Regis. THE GEOLOGICAL MAGAZINE. NEW SERIESHY DECADE “lili WOLERIV. No. X.—OCTOBER, 1888. Cnusnrennyp Arn /Namenanehrasnsy) T.—On Errow anriquus, BroperiP, sp., FRoM THE Lower Lias, Lymz-Reets, Dorset. By Henry Woopwarp, LL.D., F.R.S., V.P.G.S., of the British Museum (Natural History). (PLATE XII.) O far back as the year 1820, Schlotheim described in his Petre- factenkunde, vol. i. p. 37, certain Oolitic Crustacea from Solen- hofen, which he called Macrourites; but forms belonging to more than one genus were included by him under this name. We are indebted to M. Desmarest, in 1822, for the earliest descrip- tion of the genus Eryon from the Lithographic Stone of Solenhofen.’ A form of Eryon was described in 1835, from the Lias of Lyme- Regis, by Mr. W. J. Broderip,? F.R.S., under the name of Coleia antiqua. In the same year Prof. von Meyer described an Eryon from the Upper Lias of Rabenstein, Bavaria, under the name of EF. Hartinanni.’ In 1849 Prof. McCoy‘ described, but did not figure, an Hryon from the Lias of Leicestershire under the name of H. Barrovensis. Ten species of Eryon have been described by Schlotheim,’ Minster,® Etallon,’ Germar,® Fraas ° and Oppel,” mostly from the Lithographic Stone of Solenhofen. Eryon™ Eschert was described by Oppel from the Lower Lias of Schambelen, Switzerland, and Eryon Edwardsi by M. Moriére,” from the U. Lias of Calvados, Normandy. In 1866 I described and figured several British Liassic species of Eryon,® viz —E. Barrovensis, E. Wilmcotensis, E. Brodiei, E. crasst- chelis, and E. Moorei ; also E. Oppeli from Solenhofen. In 1881 I added another British species of Eryon, E. Stoddart, from the Stonesfield Slate, and EH. Neocomiensis,” from the Lower Cretaceous of Silesia. 1 Nat. Hist. Foss. Crust. 1822, p. 128. 2 Trans. Geol. Soc. 1835, 2nd ser, vol. v. p. 172, pl. 12, figs. 1 and 2. 3 Bronn, Jahrb, 1836, p. 329. 4 Ann. Mag. Nat. Hist. 1849, p. 172. > Petrefactenkunde, 1822, p. 35, tab. 3, fig. 2. 6 Beitrage zur Petrefk. 1839, vol. ii. p. 2. 7 Etallon in Bullet. Soc. Geol. de Fr. 1858, xvi. p. 169, t. 4, figs. 1-3. 8 Germar in Keferstein. Deutschl. 1827, iv. p. 99. 9 Wiurttemb. naturw. Jahresh. 1855, xi. Jahre. p. 94. 10 Pal. Mittheil. 1862, p. 8, tabs. 1-3. 11 Pal. Mittheil. 1862, p. x. t. 1, fig. 1. 22 Bull. Soc. Linn. de Normandie, 1864, tome viii. p. 89, pl. vi. 8 Quart. Journ. Geol. Soc, 1866, vol. xxiii. p, 493, pl. xxiv. and xxv. 14 Grot. Mae. 1881, p. 529, Pl. XIV. Fig. 2. 15 Grou. Mae. 1881, p. 530, Pl. XIV. Fig. 1. DECADE HI.—VOL. Y.—NO. X. 28 434 Dr. H. Woodward—On the genus E’ryon. In 1883 M. Moriére described a second species of Hryon under the name of H. calvadosi' from the Upper Lias of Calvados. In 1884 Mr. C. Spence-Bate, F.K.S., figured and described a species of Eryon from the Lias of Lyme-Regis, Dorset, under the name of Archeastacus Willemesii.2 I ventured to point out, in a footnote to his paper (see Grou. Mac. 1884, p. 810) that the specimen so described was almost certainly identical with Hryon crassichelis, H. Woodw., 1866 (see Quart. Journ. Geol. Soc. 1866, vol. xxii. p. 497, pl. xxv. fig. 2). In August, 1888, the two fine volumes xxiv. (text and plates) of the “Challenger” Report on the Crustacea-Macroura by Mr. C. Spence- Bate, F.R.S., were received by me. In this magnificent Monograph the author discusses, under “ Morphology,” p. xv, and again under the Eryonide (pp. 100-120), both the past and present representa- tives of this family, and he gives a conjectural restoration of his “ Archeastacus Willemesii”’ (2? = Eryon crassichelis, H. Woodw.), which, however, differs considerably from the actual specimen, as may be seen by a comparison of the carefully-drawn Plate X. Grou, 1884, Mag. with the “Challenger”? woodcut on p. 117. The most important points to be noticed in the new figure are, the omission of the articulation (digresis) in the outer lamella (exopodite) of the sixth segment of the abdomen (forming the “rhipidura,” or “tail-fan” of Spence-Bate) ; the exaggerated size of the scaphocerite or antennal scale—certainly more than twice the natural size; and the incorrect representation of the basal joints of the antenna. This latter is due to Mr. Spence-Bate having mistaken the three terminal joints of the exopodite of the maxillipede (preserved in the fossil on the right side) for the basal joints of the antenna. The antennules in the original specimen do not bend outwards over the antenna as here represented, the former with their short bifid multiarticulate flagella being directed forwards, and the latter with its single flagellum, and short ovoid basal scale, being curved outwards. Lastly, it is quite certain that the latero-anterior margin of the carapace is not perfect in the fossil, and does not justify the representation given of a smooth rounded margin; the evidence on the surface of the carapace of a cervical furrow bifurcating on each side justifies the assumption that the margin would be intersected by two indentations one at the end of each branch of the cervical furrow, and marked by a more or less pointed lobe enclosed between these two indentations, a form of carapace most characteristic of the genus Hyon. In 1835 Mr. W. J. Broderip described in the Transactions of the Geological Society of London (2nd series, vol. v. pl. 12, figs. 1, 2, p: 172), a new Macrourous Decapod Crustacean from the Lias of Lyme-Regis, which he named Coleia antiqua. The larger fossil figured by Broderip is very imperfect, but the smaller is more com- plete; both examples display sufficient evidence in the carapace and appendages to have justified: Dr. Oppel in his conclusion that they belonged to the genus Hryon (Pal. Mittheil. 1862, p. 11). 1 Bull. Soc. Linn. de Normandie, 1883, sér. 3, tome vii. pp. 1-10, pl. i.-1i. 2 Grou. Mac. 1884, Dec. III. Vol. I. Pl. X. p. 307. Dr. H. Woodward—On the genus Eryon. 435 Another example of Eryon ( Coleia) antiquus from the same locality and formation having been obtained for the British Museum, it seems to me to deserve to be recorded and figured (see Plate XII.), as this is evidently a rather rare species in our Lias. Description.—The whole Bppcimen measures 114 centimétres in length; the cephalothorax is 54 centim. long and 5 &. at its broadest part just behind the cervical. furrow, and 4c. wide at its posterior border. The hinder border is nearly straight, being but slightly arched, or concave, forwards. Ata distance of 3c. from the pos- terior border there is a well-developed rather incurved tooth or spine marking the posterior margin of the first lateral indentation of the carapace 5mm. deep. At 3% centimétres from the posterior border the 2nd lateral roundly-incurved tooth arises. Here the carapace becomes narrower, being only 44c. in breadth. This 2nd rounded serration also marks the second lateral indentation 6mm. deep; this may be called the cervical notch, as it unites with the cervical furrow, which here crosses the carapace in a clearly-marked obtusely V-shaped line. In front of this cervical notch, the carapace again expands, forming a rounded lobe on each side, ending in a third antero-lateral tooth; here the carapace has contracted to a breadth of 24 centimétres; this tooth forms the outer border of the orbital fossa 6 mm. broad; the inner margin of which is formed by a spine 6 mm. long, which rises up on either side of the deep frontal fossa, 12 mm. across, and broadly U-shaped, which occupies in the cara- pace of Hryon that space usually filled by the rostrum in other Macroura, but which is not developed in the Eryonide. In this frontal fossa the antennules are seen with their three basal joints and their bifid flagella, the outer flagellum being 11 mm. long and the inner 16mm. _ Just inside the antennules are preserved the four distal joints of the two palpi (or endopodites) of the 3rd or external pair of maxillipedes. Only portions of the flagella of the outer antenna with their basal joints are preserved. Near the base of these, the flattened remains of the ophthalmopods are seen lying in the orbital fossa on each side. The great length of the first pair of chelate thoracic legs is very characteristic of H. antiquus, and strikingly in contrast with all the other species of Hryon, save H. bilobatus, E. longipes, and EH. Reden- bacheri, from Polenhofen (see Oppel’s Pal. Mittheil. pp. 16-18, tab. 3, figs. 2, 3,6). They are, in our fossil, 114 centimétres long. The 2nd pair, also chelate, are much smaller, being 44 c. long. The ord and 4th pairs were also chelate and the Sth pair simple. The abdomen measures 64 centimetres in length, including the telson, which is 2 c. long. Its widest part is at the 2nd segment, which is 384c. wide, the 6th being 24c.: the breadth of the swimmerets of the tail is 6Lc. The ‘telson is 14 mm. broad. The sternal arches of the segments are narrow near the centre, with wide intersternal membranes : ; but they become broader near their rounded epimeral borders. Hach somite or segment bears upon the centre of its tergal arch a strong tubercle; the whole surface of the segments being coarsely 436 Dr. H. Woodward—On the genus Eryon. granular. The telson has three longitudinal ridges upon it. The tail-lobes or swimmerets are broadly rounded, and the outer plate has a dizresis across its lower extremity. The surface of the carapace is strongly granulated, the centre or dorsal line being marked by a strong line of tubercles which die out forwards, just beyond the cervical furrow. In addition to the dorsal ridge two lateral lines of smaller tubercles further subdivide the carapace longitudinally, marking off the branchial region on either side. The lateral margins of the carapace are also marked by minute spines and tubercles. Referring again to Mr. C. Spence-Bate’s remarks on the genus Eryon, including as at present constituted many species from the Solenhofen Limestone in which the dizresis, or suture dividing the outer lobe of the caudal fin, is absent, and many from the English Lias, ete., in which it is distinctly present, Mr. Spence-Bate contends —and he is probably justified in his contention—that the absence or presence of this dizresis is of generic, if not of family, value; and further that there are many other distinctive characters amongst the various species of Eryon which are of sufficient importance to constitute generic differences. He has separated from the genus Eryon, under the name of Archeastacus Willemesii, a Liassic form from Lyme-Regis (see Grou. Maga. 1884, Pl. X. and p. 3807; see also “Challenger” volume, 1888, p. 117), which he believed had no digresis, but which has in fact a well-marked one. Apart from this, it has no salient character which would entitle it to be treated as generically distinct from other Liassic forms of Eryon. But if the presence or absence of a digresis in the outer lobe of the tail-fan be deemed of generic value, then all those forms in which this suture is absent, must be retained in the genus Eryon,' whilst those in which a digresis is present, must form a new genus. Unfortunately the name Archezastacus, proposed by Mr. Spence- Bate, cannot stand, as it was given in error to a form which its author believed to be destitute of a digresis, whereas it possesses one. But if the Liassic species must be separated for this reason from the genus Hryon, then Broderip’s genus Coleia (1835) should be revived, as having the priority, by more than fifty years, over the generic name proposed by Spence-Bate. Mr. Spence-Bate quotes the writer as to the rarity with which the eyes are found preserved in fossil forms of the genus Hryon. He writes: “'The eye is but rarely if ever preserved, and Woodward says, ‘has never been positively determined, and the peduncle on which it is supposed to stand frequently appears as if it were biarticulated ; but I have never seen a specimen, or the figure of one, in which the perfectly-formed eye has been found so as clearly to determine its form and character.” I cannot find the above italicized quotation, but I do say (Quart. Journ. Geol. Soc. 1866, p. 496): “The eyes, but rarely preserved, are placed ””—in Hryon Barrovensis—‘“ near the base of the scale of the outer antenne.” Again under /. Brodiei (op. cit. p. 498): “In this specimen, one eye is preserved in siti.” 1 The genus Evyon was founded by Desmarest on specimens from Solenhofen which have xo dieresis in the tail-fan. Dr. H. Woodward—On the genus Eryon. 437 In Oppel’s “ Palzontologische Mittheilungen” (1862) he figures several Hryon from Solenhofen; e.g. £. ‘arctiformis, Schlot. sp. (op. ae Tab. 3, He 1), and he marks (0, 0) “ Augenstiele,” and on Mabe 2, figs. 15 2; Me (0, 0) “ Hinschnitte im Cephalothorax fiir die eee In the description of the figure given by him (“Challenger” Report, p. xv) of Hryon calvadosii (after M. Moriére) ‘the orbits,” says Spence-Bate, “for the reception of the organs of vision are well preserved.” Bearing in mind the usually delicate nature of these organs, it is not surprising to find them more often represented by their orbital vacuities than by the eyes themselves.! We cannot follow Mr. Spence-Bate in his conclusions that we find ‘in the same geological epoch some specimens of Zryon that are blind, and others with large and probably well-developed organs of vision” (op. cié. p. xvi). Such a deduction, based upon our present imperfect knowledge of fossil forms, would be as erroneous as to conclude that the Venus of Milo was originally sculptured without arms because they are now reduced to stumps. During the cruise of the “Challenger,” two genera of deep-sea Crustaceans allied to Hryon were obtained by Dr. v. Willemoes- Suhm, the late talented Naturalist to the Expedition, whose lamented death occurred before the completion of the voyage. By the kindness of Dr. John Murray, F.R.S.E., the Director of the “Challenger” publications, I am permitted to reproduce figures of these very remarkable living representatives of this well-marked and ancient family of Jurassic Crustaceans. The first of these, Polycheles cructfera, was dredged off Sombra Island, West Indies, in a depth of 480 fathoms ‘(op. cit. p. 127). Another specimen is mentioned (at p. 100) as having been dredged in the middle of the North Atlantic at a depth of 1900 fathoms, or rather more than two miles from the surface! (see Woodcut, Fig. 1). “The eye is lodged in a narrow cleft of the dorsal surface of the carapace, and projects beneath the antero-lateral angle of the cara- pace in the form of an obtuse point” (op. cit. p. 127). “ The animal,” says Mr. Spence-Bate, ‘“‘can have had only a very limited range of vision outwardly, by the aid of one lens above, and another below and a little in advance, and even this, from the apparent density of the cornea, must have been of a very imperfect character” (op. cit. p. 128). Another species, Polycheles Helleri, Bate, dredged to the north of New Zealand, in a depth of 520 fathoms, and again north of New Guinea, at a depth of 1070 fathoms, appears to have had equally — imperfect vision (op. cit. p. 139). The second form, Pentacheles euthrix (Woodcut, Fig. 2),was dredged off the Kermadec Islands in depths of 520 and 680 fathoms; and again off Matuku, in 315 fathoms. “The ophthalmopod is lodged in a notch in the carapace that is 1 In the recent forms described by Mr. Spence-Bate the eye was found to be almost entirely concealed beneath the antero-lateral angle of the carapace, see wood- cut of ophthalmopod of Pentacheles gracilis (‘« Challenger” Report, or CrusTacea- Macroura, vol, xxiv. p. 114, fig. 28; also vol. xxiv. “plate xvii. figs, Ca, Cii.a, C iii. a.) 438 Dr. H. Woodward—On the genus Eryon. LULL Lae rep SS (SEE: LHS = Z BG Oo oe ee ” CE PS £4 Fie. 1. Polycheles crucifera. From a drawing by Dr. v. Wintemors-Suum. (Reproduced by permission from the ‘‘ Challenger’? Report on Crustacea- Macrura, vol. xxiy. p. 131, fig. 31.) Dr. H. Woodward—On the genus Eryon. 439 PY, PFA i: — a Fie. 2.—Pentacheles euthrix. From a drawing by Dr. y. W1tLEMors-Suum. (Reproduced by permission from the ‘“ Challenger” Report on Crustacea- Macrura, vol. xxiv. p. 150, fig. 33.) 440 Dr. H. Woodward—On the genus Eryon. much broader at the anterior margin, and narrower posteriorly ; it carries a small, pointed cusp on the anterior surface, and passes outwards beneath the projecting angle of the carapace, and terminates in two small nodules, one on the outer, and the other on the lower side” (op. cit. p. 151). Three other species are recorded by Mr. Spence-Bate, viz.— P. obscura, north of New Guinea, depth 1070 fathoms ; P. levis, between Samboagan and New Guinea, 500 fathoms; P. gracilis, off Kandavu Island, in 610 fathoms. It can hardly be doubted that in these remarkable deep-sea forms we have the last survivors of a once numerous family of Crustacea- Macrura with broad and flattened carapaces, destitute of any rostrum, serrated more or less along their lateral margins, and generally marked by a strong cervical furrow which is usually branched laterally. That these modern forms should either be quite blind, or have but imperfect vision, does not seem extraordinary when we con- sider the very great depth at which they have been found living ; but it is quite certain that the fossil forms, both of the Oolite and Lias, inhabited comparatively shallow near-shore waters, as is proved by the nature of the deposits in which they occur, and the numerous terrestrial and shallow-water organisms found embedded with them. The absence of vision in the fossil forms cannot therefore be proved by comparing them with the recent ones, whose conditions and surroundings are so different. The species of Hryon from the Lias, having all, apparently, a dieresis in the outer lobe of the caudal fan, are evidently an older or less specialized form than those of the newer Solenhofen Stone (Upper Oolite), in which the dieresis is absent, the outer lobe of the caudal fan being in one piece; and this is the case also in the surviving deep-sea species. In a footnote to the “Challenger” Report on Crustacea-Macrura, Mr. Spence-Bate writes at p. 120 :—“ In the Quart. Journ. Geol. Soc. (1866) vol. xxv. fig. 1, Dr. Woodward delineated by the help of the fine examples in the cabinet of the Rev. P. B. Brodie, F.G.S., and those in the British Museum, a completely restored figure of Eryon barrovensis, M‘Coy, in which the scaphocerite is fixed at the extremity of a peduncle that is independent of that of the antenne. This condition not being in accordance with the anatomical structure of the Macrurous Decapoda, I am induced to think that the small pedicular plate at the extremity of the third pair of maxil * is in- tended, of which a drawing is given, fig. 31, p. 135, in this Report, and which in some recent species extends beyond the frontal margin.” In my figure referred to, the artist has correctly represented the pro- jecting latero-anterior angles of the frontal margin of the carapace of LE. Barrovensis as partially concealing the broad basal joint of the antenna, giving to it the appearance as if the antennal scale (scapho- cerite) was articulated to a distinct base, separate from the antenna. As such a structure is unknown, it is extraordinary that this should have misled so old and experienced a Carcinologist as Mr. Spence- Bate, and that he should not have turned to the text, where (p. 496, O. Reid and H. N. Ridley—Fossil Arctic Plants. 441 op. cit.) it is distinctly stated that, “Hach of the outer antennz has a large oval scale attached to its broad basal joint.” It would be quite impossible, in the scope of the present brief article, to discuss the numerous points of interest and importance bearing upon the Aryonide which the publication of Mr. Spence- Bate’s fine Monograph raises, but, I may mention, that in an early Paleontographical Monograph on the British Liassic Crustacea, I hope to treat this subject with the fullness which it deserves. Il.—Fossizr Arctic Puants From THE LAcustRINE Deposit AT Hoxne, IN SUFFOLK.! By Cuement Rei, F.G.S., and H. N. Ripiny, M.A., F.L.S. EAR the village of Hoxne, close to the northern border of Suffolk, and about five miles east of Diss, lies the well-known lacustrine deposit from which Paleolithic implements were obtained more than 90 years ago. This deposit has been so well described that it may seem presumptuous to imagine that there is still any- thing new to be said about it. But it so happens that every observer up till now has studied the deposit either from an archeological or from a geological point of view. No one has paid special attention to the character of the associated plants, or to the climatic conditions which these plants indicate. The earliest description of the deposits at Hoxne is an excellent one contained in a letter by John Frere to the Secretary of the Society of Antiquaries.2 This is dated as far back as 1797. It gives a clear account of the exact mode of occurrence of the imple- ments, and enables us to recognize without difficulty the relative position of the implement-bearing deposits, and of the beds with arctic plants described in this paper. The section given by Frere is :— iemViemetablerearth asc .csueucncscuscseeeseacctc sete. tens esesecseasetcleveseccese 1} feet. DMA Onl Mk irae acne eceis ada sce aeRM CRS SE CE uM ENE cada raion ses sclewaeele TE 55 3. Sand mixed with shells and other marine® substances.................. 1 foot. 4. A gravelly soil, in which the flints are found, generally at the rate Of iven OLN SEX IME A; SQUATE RV ALC Maatsseee. ssecee from more recently dis- covered specimens, that the English Cretaceous species was more specialized in every respect than any of the typical forms of Hybodus; and quite lately it has been proposed * to regard this fossil as generically distinct, with the new name of Synechodus. It now appears, indeed, that ‘ Hybodus” dubrisiensis is much more nearly related to Palceospinaz than to the typical Hybodus. This is well shown by the almost complete dentition of one jaw, exhibited in a fine specimen from the Chalk of Sussex, preserved in the Willett Collection in the Brighton Museum ; and the oppor- tunity of making known this important new fossil—kindly afforded by Henry Willett, Esq., and the Chairman of the Museum Committee (Edward Crane, Esq.)—seems a fitting occasion for briefly sum- marizing our present knowledge of the skeletal and dental characters of the fish. All the cartilages are only superficially calcified, but the thin hardened layer is comparatively resisting, and it has thus been sufficiently preserved in some cases to indicate the precise contour of several parts of the skeleton. Head.—Nothing worthy of note has been observed in connection with the cranium; but the mandibular and hyoid arches are well known and of great interest.° A facette upon the superior border of the pterygo-quadrate cartilage may almost certainly be regarded as indicating a post-orbital articulation with the cranium; and in correspondence with this arrangement the hyomandibular element is remarkably slender. There is thus considerable resemblance between the skull of Synechodus and that of the existing Notidanus ; both exhibiting a very primitive condition of the mandibular and hyoid arches, and showing a tendency to specialization in one and the same direction. 1 A. E. Reuss, “ Verstein. bohm. Kreideform.,”’ 1845-6, pt. i. p. 2; pt. ii. pp- 97, 98, with figs. 2 §. J. Mackie, “On a new species of Hybodus from the Lower Chalk,’ The Geologist, vol. vi. (1863), pp. 241-246, pl. xiii. 3 Smith Woodward, “On the Relations of the Mandibular and Hyoid Arches in a Cretaceous Shark (Hybodus dubrisiensis, Mackie),’’ Proc. Zool. Soc., 1886, . 218-224, pl. xx. 4 Smith Woodward, “ A Synopsis of the Vertebrate Fossils of the English Chalk,”’ Proc. Geol. Assoc. vol. x. (1888), p. 288. 5 See figures in Proc, Zool. Soc. 1886, pl. xx. A. Smith Woodward—On the Genus Synechodus. 497 Dentition.—In Mr. Willett’s example of the dentition of Synechodus dubrisiensis, already referred to, about 140 teeth are displayed in their natural relative positions; and the fossil is shown, of twice the natural size, in the accompanying Woodcut, with the first and second teeth and one of each of the alternate succeeding series, still further enlarged separately. There are eleven dental series upon either ramus of the jaw, each of those posteriorly placed com- prising as many as eight or nine teeth, while those near the symphysis have not more than six. There is no median symphysial row of teeth, and the first pair (1.) is extremely small. In the latter the principal coronal cusp is long and slender, its height being equal to the entire width of the tooth; and there are two small denticles in front and one behind. The teeth of series 11. are nearly four times as wide as those of no. 1., with the principal coronal cusp still very prominent and flanked in front and behind by three large denticles and one smaller point, of which those behind are the more widely spaced. The teeth of series 111. are very similar to those of no. .; but in the teeth of series mm. and y. the principal cusp rapidly becomes stouter and less elevated, and there are five denticles in front, while only three or four can be distinguished behind. In serles vi. to 1x. the size of the teeth only gradually decreases back- wards, but the principal cusp becomes very short and stout, thus more resembling the lateral denticles, which are still very numerous and placed well apart. In these teeth, the denticles are five or six in number, both in front and behind. In series x. the teeth are only about two-thirds as wide as those of no. 1x., while those of series xI. are still smaller by one-half; and in both of these all the coronal prominences have become insignificant, though yet faintly indicated by a beaded contour. The base of the crown in all the teeth is marked by fine reticulating wrinkles, and the lower portion of the coronal cusps is often vertically striated. On comparing the teeth of this fossil with the few examples of S. dubrisiensis already described, one important difference will at once be noted. Whereas in Mr. Willett’s specimen, the most anterior teeth are very small and delicate, some other fossils exhibit teeth in a corresponding position of a very large and robust character, with several feebly marked denticles on each side.’ One specimen in the British Museum (No. 41675) suggests that the latter pertain to the upper jaw; and, in that case, the Brighton fossil may represent the lower dentition. There can be no doubt, indeed, that the two types belong to one and the same species; but whether the differences in the anterior teeth depend merely upon their pertaining to one or the other jaw, or whether one type is referable to the male and the other to the female, remains yet to be determined. The present writer has examined no specimen in which the small teeth and the robust teeth occur together. Axial Skeleton of Trunk.—The vertebral centra are well calcified ; but only the anterior portion of the body is yet known (Brit. Mus. 1 Proc. Zool. Soc. 1886, pl. xx. fig, 3a. DECADE III.—VOL. V.—NO. XI, 32 498 A. Smith Woodward—On the Genus Synechodus. wqnp snpoysauhgy jo uorytyUueg [mnesnyy uoysug “go yg “bsy “aZaTITAy AUNAP Jo uoroaT[09 | ‘sisuars *xossng ‘yreyO ‘ds oryoeyy A. Smith Woodward—On the Genus Synechodus. 499 No. 49032). All the vertebre are distinctly “‘asterospondylic” in structure, and the centra are mostly deeper than long. Appendicular Skeleton.—Kach half of the pectoral arch consists of a single slender cartilage, produced upwards into an attenuated extremity, and very similar in form to the corresponding element both of Palgospinaz and of Hybodus. External Dermal Structures.—A fine, apparently sparse shagreen covered at least certain portions of the body; and a few of the granules are well preserved upon one small fragmentary head in the British Museum. Some granules are smooth and quadrate in form, but many are more or less oval, ridged and grooved in the direction of their long axis. Affinities—The dentition of Synechodus, as long ago recognized, indicates the systematic position of the fish to be in the Hybodont section of the great family of Cestraciontide. Many of the detached teeth cannot be distinguished from those of Hybodus; but, as already remarked, a comparison of the complete dentition described above with the dentition of Palzospinax priscus from the Lower Lias of Lyme Regis,' shows a still more exact correspondence in almost every feature. With Palgospinax, also, Synechodus agrees in the character of its shagreen; and the vertebre in the Cretaceous genus only differ from those of the Liassic fish in their slightly higher stage of development. The fact that no Selachian dorsal fin- spines have hitherto been found in the Chalk, except small smooth spines indistinguishable from those of Cestracion and Palgospinaz, is also suggestive of the correspondence of the two genera under comparison in the nature of these dermal defences. The more specialized character of Synechodus, indeed, is the only justification at present for its generic separation; and it may be added that Palgospinax is certainly one of the Cestraciontide (Hybodontide), being definitely separated from the Spinacide, with which it has hitherto been associated, by the possession of a distinct anal fin (Brit. Mus. no. P. 1296). Distribution.—The earliest evidence of Synechodus with which the writer is acquainted occurs in the Neocomian of Kent, whence have been obtained some anterior teeth with an attenuated principal coronal cusp. Other teeth have been described from the Lower Cretaceous of Amuri Bluff, New Zealand, under the name of Odon- taspis sulcata.2, A few teeth, of still another specific type, are met with in the English Gault. A single example from the Cambridge Greensand is preserved in the collection of Thomas Jesson, Hsq., of Northampton. 8S. dubrisiensis occurs in the Lower, and probably also in the Upper Chalk; there is evidence of other forms in the uppermost Chalk of Norfolk; and one or more species are repre- sented in the Lower Chalk of Saxony, Bohemia, and Russia. 1 Sir Philip Egerton, ‘‘ Figs. and Descrips. Brit. Organic Remains” (Mem. Geol. Surv.), dec. xii. (1872), pl. vu. 2 J. W. Davis, ‘On the Fossil Fish Remains of the Tertiary and Cretaceo- Tertiary Formations of New Zealand,” Trans. Roy. Dublin Soe. [2] vol. iv. (1888), p. 25, pl. v. figs. 11—13. 500 A. Smith Woodward—On a Species of Onychodus. VI.—Nore on THE OccURRENCE OF A SPECIES OF ONYCHODUS IN THE Lower Oup Rep Sanpstone PassaGre Beps or Leppury, HERe- FORDSHIRE. By A. Smiru Woopwarp, F.GS8., F.Z.8.; of the British Museum (Natural History). URING a recent visit to the University Museum at Oxford, I observed in the Grindrod Collection an interesting small fossil apparently adding to the known fauna of the Ledbury Passage Beds a remarkable type of fish, hitherto only met with in the Middle and Upper Devonian of the United States. Through the kindness of Professor Green, I have since had the opportunity of studying this specimen in London; and it is shown, of twice the natural size, in the accompanying Woodcut. It may be regarded as an imperfect example of the so-called ‘‘intermandibular arch” of the extinct ganoid, Onychodus, described by Prof. Newberry’ from the Corn- iferous Limestone of Ohio, and the Chemung Group of Delaware County, New York. The fossil is, for the most part, only displayed in section, owing to the unfortunate plane of fracture of the matrix ; but the upper- most of the vertical series of teeth, as preserved, exhibits the unbroken outer surface for about half of its length, and this enables Intermandibular Arch, or Presymphysial Bone, of Onychodus anglicus, A. 8. Woodw., Lower Old Red Sandstone Passage Beds, Ledbury, Herefordshire. Twice nat. size. [Grindrod Collection, University of Oxford. ] the cylindrical form and unornamented character of the dental crown to be determined. There is a curved plate for the attachment of the teeth, scroll-shaped in section, the attenuated lower extremity being considerably in-rolled. The teeth have the appearance of being directly fused to the base, arranged along its convex side; and they obviously decrease in size from above downwards, though the distal portions of all but the uppermost are considerably destroyed. The upper tooth, as already remarked, is slender and cylindrical in section, with a smooth surface, perhaps only marked with one faint longitudinal groove on each side; and the distal half of the crown is sharply directed upwards. Beneath this tooth are prominent remains of three others, similarly shaped, and closely placed together at their bases; and evidence of either one or two still smaller teeth is distinguishable yet more inferiorly. Ferruginous matter has penetrated the interstices of the fossil, 1 J. S. Newberry, Geol. Survey of Ohio, vol. i. pt. ii. (Paleontology), pp. 296— 302, plates xxvi., xxvii, A. Smith Woodward—On a Species of Onychodus. 501 and so rendered its minute structure to a certain extent recognizable. The base is conspicuously vascular, except in a thin, sharply-defined layer forming the concave margin; and each tooth is likewise con- stituted mostly of vascular tissue, with a thin, dense outer layer. A very small cavity also appears to occupy the centre of each dental cone. The genus Onychodus was originally founded by Prof. Newberry upon detached teeth similar to those of the Ledbury fossil, dis- covered in the Corniferous Limestone of Ohio. These teeth were at first supposed to be referable to the great Placoderm, Macropetal- ichthys, occurring in the same beds; but their discovery soon after- wards in connected series naturally led to the suspicion that they might rather pertain to a Selachian. Still later, the problematical dentition was found associated with cranial plates, tooth-bearing maxille and dentary bones, and numerous round scales; and in 1878, complete proof of its exact position in the jaws of the original fish had at last been obtained. It appears that the slender bony arch is a mesial element fitting in a well-marked groove at the symphysis of the dentary bones; while the long, sigmoidally-curved teeth project directly forwards in front. The head-bones are numerous, and the large round scales are deeply overlapping, being ornamented much like those of Glyptolepis ; whence Prof. Newberry concludes that Onychodus was most probably one of the great group of Crossopterygidee. The fossil now under discussion is thus referable to a “‘ Ganoid,” and it evidently represents the presymphysial bone of some later genera (e.g. Aspidorhynehus and Belonostomus), even if it be not altogether homologous with that element. The appearance of the series of teeth is at first suggestive of a dental succession like that of Selachians; and in this connection it would be interesting to know precisely the histological characters of the fossil. Though comparatively abundant, none of the American examples seem to have been yet examined microscopically ; but it is to be hoped that some such investigation may soon be made—more especially as comparisons have already been suggested with the problematical Carboniferous Hdestus.? The coiling of the inferior extremity of the base in the Ledbury fossil has not hitherto been noted in the American specimens; and this may be either a normal feature, or merely a post-mortem accident to a possibly pliable tissue. Other differences, however, of at least specific value, are also observable between this and the described American types of “intermandibular arch”: the new fossil is much smaller than those already known, and the size of the teeth is apparently less uniform. Awaiting further evidence, there- fore, for more precise definition, the species of the Ledbury Passage Beds may receive the name of Onychodus anglicus. 1 Fanny R. M. Hitchcock, ‘‘On the Homologies of the so-called Spines of Edestus,’’ Proc. Amer. Assoc. Ady. Sci. 1887. See also J. S. Newberry, ‘‘ On the Structure and Relations of Hdestus,” Ann. New York Acad. Sci. vol. iy. (1888), p. 116. 502 Prof. FE. Hull—The Jordan and Dead Sea. VII.—Norts on Mr. IJ. C. Russety’s Paper on THE JoRDAN-ARABAH AND THE Deap SEA. By Professor Epwarp Hutt, LL.D., F.R.S. HAVE been very much interested in reading Mr. Russell’s two communications published in the Gxotogican Magazine for August and September last. The analogy which he draws between the history of the Dead Sea valley and that of some of the lake valleys in the western part of North America is instructive as showing how similar physical features can be accounted for on similar principles of interpretation over all parts of the world. Mr. Russell very properly draws attention to the paper by his colleague Mr. G. K. Gilbert on ‘The Topographical Features of Lake Shores,” in which principles of interpretation of physical phenomena are laid down applicable to lakes both of America and the Jordan-Arabah valley. With some of Mr. Russell’s inferences regarding special epochs in the history of this valley I am very much disposed to agree; more particularly in reference to the mode of formation of the Salt Mountain, Jebel Usdum; or rather, of the salt-rock which forms the lower part of its mass. If this inter- pretation be correct, it removes the difficulty of understanding why the rock-salt is confined to one small corner of the lake, which, at the time the salt was in course of formation, was vastly more extensive than at present. The case of the arm of the Caspian known as Kara Bughaz, which Mr. Russell cites, seems remarkably apposite to that of the Southern bay of the Dead Sea; and I feel obliged to the author for his sugges- tion. In reference to Mr. Russell’s statement that ‘‘we ought to look for an unconformity between the upper and lower lake beds due to the erosion of the lower member,” J wish to take this oppor- tunity of referring again to the peculiar structure in the rock-salt near the northern end of Jebel Usdum, where the white laminated marls, forming the upper part of this plateau, are seen resting horizontally on a mass of rock-salt, having an oblique structure ; that is, traversed by planes sloping southwards at an angle of about 20°-25°. J made a sketch of this part of the cliff in my note-book, but from inability, through lack of time, to examine into the phenomena with more care than can be done from horse-back, I thought it prudent not to refer to the matter in the Geological Memoir,’ further than to notice it. My special purpose in this communication is to offer some additional information to that already given on the question whether or not the Jordan-Arabah valley originally communicated with the ocean through the Gulf of Akabah. Mr. Russell is not satisfied with the information already before him regarding the nature of the watershed of the Arabah. I have, therefore, referred back to my 1 «The Jordan-Arahab Depression and the Dead Sea,” Gzon. Mac. Aug. and Sept. 1888, pp. 337-244 and 387-3965. * Gilbert, Fifth Annual Report U.S. Geological Survey (1883-84). 3 Memoir on the Physical Geology of Arabia-Petraea and Palestine, p. 84 (1886). _ Prof. E. Hull—The Jordan and Dead Sea. 503 notes, which are rather full on this very subject, though I did not consider it necessary to give them in extenso in the Geological Memoir, or in Mount Seir. On referring to the large Map of the Arabah Valley in the Memoir (facing p. 187), it will be seen that the watershed (Lat. 30° 10’ N.) is formed partly of a limestone ridge, called Er Rishy, and partly of “gravel of the Arabah.” ‘This gravel extends for several miles down both slopes of the watershed, and is sometimes overspread by blown sand, or else by alluvium. On the west side it is bounded by the steep, often precipitous, cliff of the rocks forming the eastern border of the Desert of the Tih (Badiet et Tih), and on the east by those of the Edomite hills and escarpments; and at its lowest part rises about 700 feet above the level of the Mediterranean and Red Seas,! and therefore nearly 2,000 feet above the present surface of the Dead Sea. On approaching the watershed, or saddle, from the south, it appears as a level line stretching from the northern end of Hr Rishy to the foot of the rugged hills of Edom, and about half a mile in length. It is formed of sand and gravel of considerable thickness overlying the limestone which rises from beneath on the eastern side, and which is broken off by the great Jordan-Arabah fault against the granitoid and other crystalline rocks, which here form the base of the Edomite range. This gravel has all the appearance of a fluviatile, or alluvial, deposit, formed by the streams which in flood time descend from the hills to the east; and it is well laid open to view in one of these streams, which ultimately joins the River Jeib. Between this water- shed and the first of the terraces which can, with any degree of certainty, be referred to a lacustrine origin, there is a distance of over twenty miles, and a vertical fall of about 700 or 650 feet; and as our party was scattered over the valley, we could not have failed to detect remains of such lacustrine deposits, if any such existed, above the level of those we encountered at our camp of the 12th December, 1883, at Ain Abu Werideh: at a level approximately that of the Mediterranean, and 1292 feet above that of the Dead Sea.* These horizontal beds of white marl with shells, sand, and shingle, was an entirely new feature to us all; and no doubt remains on my mind that they indicate the highest level to which the waters of the ancient Jordan-valley Lake formerly rose. An. admission on my part that the waters of the Jordan valley ever were in connection with those of the outer ocean through the Gulf of Akabah can only be made from the point of view that, during the formation of the Jordan-Arabah line of depression by the dis- placement of the strata along the great fault, and when the whole region was rising from beneath the waters of the ocean in Miocene times, some such connection existed for a limited period of time; but this epoch in the history of the valley was separated by a long interval from that of the present Dead Sea, even when standing at a level of 1300 feet above its present surface. From the time that 1M. Vignes’ determination is 787 feet (240 métres) ; that of Major, now Colonel Kitchener, is 660 feet; and that of Mr. Reginald Laurence by aneroid 680 feet. 2 Mount Seir, p. 99; Geological Memoir, p. 80. 504 Miss C. A. Raisin—Rocks from Socotra. the outer waters of the ocean were dissevered from those of the Jordan-Arabah lake by the up-rise of the land, there is no evidence that there was ever any subsequent connection by means of a stream flowing down from the North into the Gulf of Akabah. The closest approximation which, according to my view, these inner and outer waters ever made towards each other is represented in the sketch- map of that whole region in page 72 of the Geological Memoir, where a tract of ground of about 40 miles in length and rising to 700 feet in height is represented as intervening between their respective borders. VIII.—On Some Rocx-Spectmens From Socorra. By Miss C. A. Ratsin, B.Sc. I Vara specimens were collected in Socotra, near the coast, by Colonel M. Gosset, and were sent to Prof. Rupert Jones. By the kindness of Prof. Bonney I have been allowed to carry on the examination of the rocks, at University College, in connection with the Somali specimens already described. Granites.—The granites need little description, as they are clearly of types already obtained from Socotra;! they consist chiefly of felspar, often microcline, and of quartz. Hornblende crystals, evidently of early consolidation, are imbedded in the felspar. Some of the hornblende is very strongly dichroic, and changes from a faint green to a deep peacock-blue, tints which approach somewhat near those shown by glaucophane. Octahedra of magnetite occur in one fragment, and in others characteristic crystals of zircon are fairly abundant. Felstones.—Many of these seem to be quartz-felsites of the red and purple tints, mentioned by Prof. Bonney as so characteristic of Socotra. Two specimens, however, need somewhat fuller description. (1). Quartz-felsite. This is a very compact, flinty rock, dull-green in colour, blotched with white. The ground-mass is completely devitrified, with small brightly-polarizing microliths scattered through it. The porphyritic hornblende is in partial preservation, but frequently epidote appears to have formed along its cleavage- planes, and spread over the interior of the crystal. Many of the felspars are plagioclase; some have passed to an aggregate of crystalline films, but others appear clarified, with kyanite-like cleavages. The porphyritic quartz is much corroded. Some of the embayments formed of the ground-mass inclose clear, unaltered quartz, generally with a shadowy outer border, as if it had been partially melted down by the surrounding matrix (Fig. 1). In other examples, the invading ground-mass, which has an angular outline, stops short of a curved boundary, marked out by minute cavities often with moving bubbles. Corrosion of crystals has been attributed to the influence of a direct rise of temperature, or indirectly to some cause which increases the fusibility of the matrix and solubility of the crystal, such as an alteration in the amount of ' Phil. Trans. 1883, p. 282, On a Collection of Rock Specimens from the Island of Socotra, Prof. Bonney. Miss C. A. Raisin—Rocks from Socotra. 505 pressure,! or the introduction of water.2 If the change in the condition of the rock were rapid, a contraction might result, and might perhaps develope along a curve, a layer of inclosures, as in the effects from pressure demonstrated by Prof. Judd.? The strain increased, the curve might become a crack, so that the corroding magma could make its way along the weakened surface, and cause the The darkened part represents devitrified ground-mass including hornblende flakes. The dots are minute enclosures. ‘The porphyritic quartz is left clear. interrupted embayments which I have mentioned. The degradation of a crystal may be connected with planes of weak cohesion, as seems illustrated by a grain, which shows very faint, almost concentric zoning; corrosion has originated at seven or eight points along the border of the crystal, and, as it reaches successive zones, has be- gun to spread along them, result- ing in a form like three or four shallow saucers placed one above another (Fig. 2). (2). Orthoclase-Felsite. The hand-specimen is dull, and of a very pale chocolate-brown, with slight traces of fluidal structure. The rock is microporphyritic, crowded with felspars of definite crystalline form, which are de- composed, and contain brightly- polarizing films. From their form, and the occasional occurrence of 1 Tsch. Min. Mitt. Bd. viii. p. 421; A. Lagorio, Abs. in Min. Mag. 1887. British Petrography, Mr. Teall, p. 407. 2 Grou. Mac. Jan. 1888, pp. 10, 11, Lavas of Krakatoa, Prof. Judd; Pres. Address Geol. Soc. 1885, p. 54, Prof. Bonney. 8 Q.J.G.S, 1885, p. 376, On Peridotites of Scotland. 506 Miss C. A. Raisin— Rocks from Socotra. Carlsbad twinning with simultaneous extinction, they appear to be mostly orthoclase. These felspars, and some larger crystals of a pale green hornblende, occasionally twinned, exhibit a certain orientation, which is practically the only indication of a fluidal structure seen under the microscope. Other Igneous Rocks.—In the diorites, kaolinized felspar, and hornblende mostly in good preservation, are closely intercrystallized, with some appearance of an ophitic structure. One compact black rock occurs, which seems to be of a basaltic character. Another fragment, evidently from a lava-flow, may be a basalt, in which the augite is less clearly individualized, or it may, perhaps, be better classed with the andesites. It contains vesicles, filled up mainly with calcite, but with some chlorite; it has other calcite apparently pseudomorphic, and a zeolitic mineral seems also present. A fairly large cluster of calcite scalenohedra has been sent, and appears to have been formed in or ona greenish felsite, very decomposed fragments of which are found adhering. There is one specimen of a compact black rock, which is rather puzzling, even under the microscope ; although it might be a very fine-grained igneous rock of rather basic character, yet it seems most probable that it consists of fine ashy material, with much fragmental felspar in good preservation. Sedimentary Rocks. (1). Argillite—This is a green flinty rock, with a marked and even banding. It is composed of fine material, and contains small angular fragments with a torn look, many of which are plagioclase. Except that the banding here is more evenly marked, probably in consequence of a pressure, which has acted across the lamination, this rock is very similar to those described by Prof. Bonney. It clearly bears out his suggestion, that the argillites of Socotra are probably not due to local contact metamorphism, but may represent some part of an old sedimentary series. (2). Grits.—In a grit, which appears to consist mainly of frag- mental felspar of more than one kind, there seems to have been a secondary deposition, probably of silica, which has remained as a cavernous skeleton, where the original grains have weathered out. Another specimen is composed, almost exclusively, of two of the constituents of a granitic rock—quartz and felspar—and is thus not unlike the Torridon sandstone of the Scotch Highlands. (3). One specimen of a reddened limestone is very full of frag- ments of Gasteropod and Lamellibranch shells, the calcite of which exhibits rhombohedral cleavage, and is of a deep red colour, appa- rently iron-stained. xcept for a few structural characteristics, these rocks are mainly interesting as being an independent collection, which, although small, agrees closely with the description already given of Socotra rocks. ‘The grit, here noticed, may be possibly of recent consolida- tion, or may belong to the sandstones, which Prof. Bonney mentions as probably present. The groups which he describes will include all the other specimens, except the fossiliferous limestone, although this might belong to the formation of the foraminiferal rock.’ ‘The _} If the limestone belongs to some other series, it might possibly be a representa-— tive of Dr. Rochebrune’s Neocomians of Ouarsanguélis land. Dr. R. H. Traquair—Old Red Sandstone Fishes. 507 granites, including among their constituents microcline and horn- blende, the felstones, the diorites and other types of igneous rock, and the argillite, are all in close relation to the specimens already described from Socotra.! IX.—Norrs on tHe NoMENCLATURE OF THE FISHES OF THE OLD Rep Sanpstone oF Great Britain. By Dr. R. H. Traquair, F.R.S., F.G.S. HE nomenclature of the fishes of the Old Red Sandstone of Great Britain, with the exception of the Cephalaspide, revised some years ago by Professor Lankester, is at present in a very unsatisfac- tory state. A vary large number of the species named by Agassiz, as well as by McCoy, were undoubtedly founded upon deceptive characters, due partly to different modes of preservation in different rocks, partly also to those apparent variations in external form, which are inevitable in such ancient fossil fishes devoid of a fully ossified internal framework, without which the original outline can- not be expected to be constantly preserved. In specimens from one locality the external ganoid surface of the scales may be well shown, in those from another it may be constantly hidden or obscured, while the proportional measurements in the very same species may vary infinitely, by the fish being lengthened out, or shortened up by changes, which have occurred after death or during the consolida- tion of the enclosing rock. These and kindred sources of fallacy can only be guarded against by long experience in deciphering such remains, coupled with the examination of an immense number of specimens. As I am at present engaged on a complete synonymic Catalogue of the Paleozoic Ganoids and Dipnoi in the Kdinburgh Museum, I shall limit myself in the following brief ‘‘ notes” to indicating a few of the principal results which I have obtained in the course of my examination of the fishes of the Old Red Sandstone. Order Drpnot. Family Diererip (Ctenodipterini, Pander). Dipterus, Sedgw. and Murch.—Four species of this genus were named by Sedgwick and Murchison, namely, D. macropygopterus, D. brachypygopterus, D. Valenciennesii and D. macrolepidotus. All four were united by Agassiz under the name of macrolepidotus, but it was clearly shown by Pander and McCoy that macrolepidotus had no place in the original definition of the genus, being possessed of rhombic instead of circular scales. The other three were maintained to be distinct by McCoy, while Sir Philip Egerton, admitting the identity of the first two, still held out for the separation of Valen- ciennesti. After a careful study of the original types in the collec- tion of the Geological Society I fully agree with Pander that D. macropygopterus, brachypygopterus, and Valenciennesii are one species, for which it is desirable to retain the last-mentioned name, given in 1 Phil. Trans. 1883, p. 273. 508 Dr. R. H. Traquair—Old Red Sandstone Fishes. honour of the distinguished French ichthyologist. As a synonym it is also necessary to include Polyphractus platycephalus, Ag., which was long ago shown to be a Dipterus by H. Miller. One species, however, exceedingly distinct from D. Valenciennesii, may here be briefly described. D. macropterus, n.sp. Traq.—Distinguished from D. Valenciennesia by the long base and broad rounded contour of the second dorsal fin, and by the thinness of the scales, which permit the outlines of the internal skeleton to be seen through them. The other fins are as in D. Valenciennesii, the pectorals and ventrals being beautifully “ archipterygial” in their contour. Lower Old Red Sandstone, John o’Groats, Caithness, Edinburgh Museum, collected by the late C. W. Peach. Order GANOIDEI. Suborder PLacoDERMATA. Family AsTEROLEPIDE. Asterolepis and Pterichthys.—There can be no doubt that Asterolepis, Eichwald, is prior to Pterichthys, Agassiz, and if Pander were right in maintaining the identity of the two genera, it would be hard to deny the preference to the first of these names. But Beyrich,} Lahusen,’ and Zittel,® accepting Sir Philip Egerton’s view that the arms in Pterichthys were articulated to ‘‘thoracic”’ plates, distinct from the anterior ventro-laterals, have founded a diagnostic mark on this supposed peculiarity, as such ‘‘thoracic”’ plates certainly do not exist in the Russian Asterolepis. But just as little do they exist in the British Péterichthys, as an examination of hundreds of specimens has absolutely convinced me that the pectoral limbs were articulated here precisely as in Asterolepis. A valid generic distinction may, how- ever, be found in the mode of articulation of the anterior median dorsal plate. According to Pander this plate overlaps both the anterior and posterior ventro-laterals, whereas in Pterichthys, though it overlaps the former, it is itself overlapped by the latter. These facts regarding the body-plates of Pterichthys were long ago known to Hugh Miller; it is interesting to add that the general structure of Pterichthys, including that of the head and arms, is very much closer to that of Asterolepis than of Bothriolepis, some of whose species,—namely, hydrophilus, Ag., major, Ag., and macrocephalus, Egert., have been included in Pterichthys. Asterolepis maximus, Ag. sp.—The large Asterolepid occurring in the Upper Old Red Sandstone of Nairn (Seabank and Kingsteps), a fragment of whose anterior median dorsal plate was figured by Agassiz as “ Coccosteus” maximus, and afterwards supposed by Hugh Miller to belong to “ Pterichthys”” major, seems to me to be referable to Asterolepis, as the anterior median dorsal plate most undoubtedly overlaps both anterior and posterior dorsal-laterals. I have now got 1 «Ueber einen Pterichthys von Gerolstein,” Zeitschr. deutsch. geol. Gesellsch. 1877, p. 754. * «Zur Kenntniss der Gattung Bothriolepis, Eichw.,” Trans. Imp. Min. Soe. St. Petersburg. 1879. 3 «* Handbuch der Paleontologie,” vol. iii. pt. 1, pp. 153-157. Dr. Rk. H. Traquair—Old Red Sandstone Fishes. 509 together an instructive series of its remains, from which it appears that the head and arms closely resembled those of that parts of the Indian ‘ Nummulitic’ formation were probably Miocene. It is worth noticing also that in Sumatra® the Orbitoidal limestone occurs at the top of a series of Tertiary beds. Op. cit. p. 122, pl. 3, figs. 17, 18, 35, 36, 37. Op. cit. p. 135, pl. 2, fig. 115; pl. 4, figs. 4-7. Op. cit. p. 536, pl. 14, fig. 3. See H, M. Jenkins’ Summary, Q.J.G.S. vol. xx. 1864, pp. 62-72. See Palontologia Indica, ser. xiv. vol. i. pt. i. Sind Fossil Corals, 1880, pp. 3-14. Verbeek, Grou, Maa. 1875, p. 479. : aonrF WON 032 Prof. G. Lindstrém—On Ascoceras of Barrande. The specimens now under consideration do not affect the question decidedly either way. The fact that all the forms mentioned above occur in the European Eocene would appear to be an argument in favour of the Eocene age of the rock. The Hocene facies of the Foraminiferal fauna may, however, be due to that eastward migra- tion which appears to have taken place, and which may account for the character of the mollusca in strata that would otherwise be looked upon as Miocene. Amphistegina and Heterostegina are rather Miocene than Eocene genera, and in an Hocene limestone of this kind one would expect to find Nummulites associated with the Orbitoides. Dr. K. von Fritsch’s Patellina trochus from Borneo! very probably comes from beds below the limestone, and in its form and size it seems identical with the small pointed forms occurring in the Cretaceous of Navarre. The large fossil Patelling have been regarded as charac- teristic of the Cretaceous and Kocene, but they undoubtedly range above the Eocene, and specimens in the Science Schools Collection from the Miocene of Jamaica occur associated with Orbitoides, Amphistegina, and Heterostegina. On the whole, therefore, though the species of Orbitoides are among those which characterize the Hocene rocks in Europe, there is good reason for defending the suggestion that the Orbitoidal Lime- stone of Borneo may be of a later date. The work on these specimens has been done in the Geological Laboratory of the Normal School of Science and Royal School of Mines, and I have to thank Professor Judd, F.R.8., for the facilities afforded me in the preparation of sections, ete. EXPLANATION OF PLATE XIV. Figures of Orbitoidal Limestone of North Borneo. Fig. 1. Stylophora, sp. X 20. Fig. 2. Section of the Limestone of the Batu Gading, showing IiZiola, Nodcsaria, Textularia, Amphistegina, Heterostegina, and Orbi- toides applanata, Gtimbel x 12. Fig. 3. O. (Discocyclina) applanata, Gbmbel. As seen in the water-polished surface of rock. a. 6. In vertical section x 2. Oh, 99 > x 100. ai. is a9 xy) Ze Fig. 4 a. O. (Discocyclina) ephippium, Sow. sp. b. Insection x 10. Fig. 5. O. (Discocyclina) papyracea, Boubée, sp. Fig. 6. O. (Discocyclina) dispansa, Sow. sp. Fig. 7. O. ( Asterocyclina), stellata, Gumbel. IJ.—On tHe Genus Ascoorr4és, BARRANDE. By Professor G. Linpsrrom, of Stockholm. TIE uppermost limestone stratum of Gotland, which occupies two-thirds of the surface of this island, and is homotaxial with the English Upper Ludlow, contains such numerous fragments of Cephalopoda, that it has been called the Cephalopodan Lime- stone. Judging from the collection in the Paleontological Depart- 1 Op, cit. p. 145. Prof. G. Lindstrém—On Ascoceras of Barrande. 533 ment of the Swedish State Museum, the number of species of Cepha- lopoda from the different strata of Gotland can hardly fall short of 200, most of them in a very perfect state of preservation, some even retaining the surface ornamentation and colour. Amongst them the genus Ascoceras (including Glossoceras), with its nine species, is the most remarkable. As the Museum has succeeded in obtaining specimens showing its morphology more completely than has hitherto been known, a few remarks on it may be made in advance of a monograph now in preparation. The annexed figure represents a longitudinal section of a speci- men from the uppermost lme- .stone. It is imperfect on the ventral side, but the characteristic septa along the dorsal side show distinctly that it is an Ascoceras. We see here two essentially different parts of the shell: firsé, a lower part in which two entire air-chambers and a portion of a third yet remain, which are fashioned, after the common Nautilidean type. The second or upper portion in immediate continuation and con- nexion with the former, is the Ascoceras properly so called. The entire shell must have been arcu- ate or gently curved, like some forms of Cyrtoceras, but it is doubt- ful if complete specimens ever existed, since several examples clearly show that the older parts Aseoceras sp., U. Ludlow, Isle of of the shell were, at certain inter- Gotland. vals, regularly cast off or decollated. The truncated end appears in all cases to have been strengthened from within by fresh linings of shelly material, and the animal continued to secrete its shell till the OY ua led STEPHEN AUSTIN AND Sons, PRINTERS, HERTFORD. / is ihe wd a ole i ’ T j a : i 5 Bytt A) Aub) ped Si Pyty Rae HNO AN 3 9088 01366 6763