conformability to older or younger beds, we find not only everywhere a marked unconformability to the Lias, but also a conformability with the Keuper, which is nowhere disturbed.

Paleontology affords evidence of the most intimate relationship of the fauna and flora of the Contorta-zone with those of the preceding and succeeding strata. Dr. v. Dittmar gives tables showing the characteristic fossils of the Contorta-beds and their affinities to older and newer forms. From these it appears that, of 162 species which are enumerated, 90 have allies in the older and 72 in the newer strata, and 12 species pass through.

Another argument, not strictly a scientific one, though sometimes made use of in discussing this question, consists in comparing the number of authors who regard this zone as Keuper with those who regard it as Liassic. The result of this is not more decisive than that obtained from other points of view. Many geologists regard this zone as a passage-bed. Such a view is considered by others as most impractical and unsatisfactory for systematic purposes. If, however, it tends to simplification, and is not unnatural, it ought to be adopted. In this case it should be left unconditionally to some high authority to fix the boundary. For this reason, as V. Alberti refers the Würtemberg Bone-bed to the Keuper, and Quenstedt classes it as the youngest member of the Trias, the author decides in favour of placing the Contorta-zone with the Keuper, the stratigraphical relations of the zone also appearing to justify this view,

Dr. von Dittmar concludes by giving a catalogue of the organic remains found in the Contorta-beds, with critical remarks thereon. [F. G. F.]

On the GEOLOGY of NEW CALEDONIA, and on some TRIASSIC FOSSILS from the ISLAND of HUGO. By M. EUGÈNE DESLONGCHAMPS.

[Documents sur la Géologie de la Nouvelle-Calédonie, suivis du Catalogue des roches recueillies dans cette île par MM. Jouan et Emile Deplanches, et de la description des fossiles Triasiques recueillies à l'île Hugon. Par M. Eugène Deslongchamps. Bull. Soc. Linn. de Normandie, vol. viii. pp. 332– 378.]

AMONGST the rock-specimens collected in the Island of Hugo, near New Caledonia, by MM. Deplanches, are some presenting a peculiar appearance on account of the immense numbers of an Avicula in them. They so nearly resemble A. salinaria, Goldf., that they are doubtfully distinguished from that species, and they form the var. Richmondiana, Zittel. The rocks of the Island of Hugo resemble in every respect those of the Upper Trias of the Alps, at Dorrenberg, where the Avicula salinaria is found by myriads; and although the appearance of the New Caledonian rock, the aspect of which resembles the Devonian Grauwacke, contrasts with the Triassic rocks of St. Cassian, Hallstatt, &c., M. Deslongchamps does not hesitate to regard the limestone of the Island of Hugo as belonging to the Upper Trias. The Avicula is associated with three species of Bra

chiopoda having a St. Cassian facies, including Spirigera Caledonica,
S. Planchesi, and Spirifer? ? The interest of this discovery is
enhanced by its application to M. Zittel's researches in the Trias of
New Zealand, at Richmond, near Nelson, where Avicula salinaria,
var. Richmondiana, Zittel, is a dominant form. The extension of the
Trias in Turkey, the Himalayas, New Caledonia, New Holland, and
New Zealand is now incontrovertible.
[P. M. D.]

The JURASSIC ROCKS of HANOVER. BY KARL VON SEEBACH. [Der Hannoversche Jura, &c. 4to. 1864, Berlin, pp. 160; one map and ten plates.] THE author occupied himself with the researches on which this work is based, in the summers of 1861 and 1862, for the sake of describing the geology of the district and of getting together a collection of North-German fossils for the museum of the Göttingen University, the authorities of which, indeed, helped him with a liberal grant. In the prosecution of his work, and in preparing the results for the press, Herr von Seebach acknowledges the kind assistance of Blasius, Braum, Credner, A. Roemer, H. Roemer, F. Roemer, A. Schlönbach, W. Schlönbach, von Strombeck, Unger, Völkner, and Witte.

In the autumn of 1862 he visited England to study the Oolitic strata, especially their upper division, and to see the type-specimens of Sowerby's Mineral Conchology'; and he offers his thanks to Messrs. Damon, Etheridge, Leckenby, Lycett, Moore, Morris, Phillips, Wright, and especially H. Woodward, for ready aid freely given. At Berlin also von Seebach studied Jurassic fossils, at the University Museum and the Mining School, and in Dr. Ewald's collection; and he acknowledges Prof. Beyrich's important assistance, with which he was favoured.

Whilst his work was at press, other memoirs on North-German geology appeared, of which he was not able to avail himself, namely, H. Credner on the Members of the Upper Jura-formation and the Wealden in North-west Germany, W. Schlönbach on the Ironstone of the Middle Lias in North-western Germany, and R. Wagener on the Jurassic Formations of the district between the Teutoburger Walde and the Weser. Two other works, by Dr. Braum and Dr. H. Credner, are expected to appear before long.

Von Seebach offers these results of his examination of the Jurassic rocks and fossils of Hanover (or, rather, of North-west Germany), not as a perfect work, to be compared with Quenstedt's Swabian Jura,' the labour of fifteen years, but as a prodromus, serving as a basis for further work in details, and to supply a general sketch such as may enable foreign geologists to compare their own with the Jurassic formation of North-western Germany,-the special works by A. Roemer, F. Roemer, and Von Strombeck having mainly local characters. A short account of the geographical conditions of the "Jura" in North-western Germany forms the first section of this work (pp. 9-13), with references to published maps and memoirs.

Von Seebach's accompanying map shows the several outcropping patches of Lower, Middle, and Upper "Jura" between Hanover and Gotha, and from the Rhine to the Elbe. The several divisions of this formation in North-west Germany form the subject of the second part of the geognostical half of the book (pp. 13-60), beginning with a few lines on the Avicula-contorta-beds, which, whether really Triassic or Jurassic, naturally are not separable from the base of the Lias in a full description of strata. Von Seebach takes as the lowest really Jurassic bed in Hanover an iron black shale, which lies on the uppermost bituminous sandstone (with Cardium Rhæticum) of the Avicula-contorta-zone, and is 10-12 feet thick, without fossils, but quite similar to the true Lias above.

A. The Lias.-The Lower Lias in North-western Germany has four members, the Middle three, and the Upper two, according to the divisions established for France and South Germany. The Lower Lias in North Germany is difficult to work out, though most minutely subdivided in Swabia. 1. The Psilonotus-beds, with Ammonites Johnstoni. 2. The Angulatus-beds, with A. angulatus and Unicardium cardioides. 3. The Arietes-beds, with A. Bucklandi, Lima gigantea, A. Conybeari, and Gryphaa arenata. 4. The Planicostabeds, with A. planicosta and A. ziphius. 5. The Brevispina-beds, with A. brevispina, A. binotatus, A. Jamesoni, Rhynchonella furcillata, Terebratula numismatis, and Spirifer rostratus. 6. The

Capricornus-beds, with A. capricornus, A. curvicornus, and Avicula cygnipes. 7. The Amaltheus-beds, with A. margaritatus, A. spinatus, Belemnites compressus, Gresslya ventricosa, Inoceramus substriatus, and Pecten æquivalvis. 8. The Posidoniæ-beds, with Belemnites irregularis, A. Lythensis, A. borealis, A. communis, Inoceramus amygdaloides, Avicula substriata, and Discina papyracea. 9. The Jurensis-beds, with Belemnites irregularis, A. dispensus, A. striatulus, A. Germanii, A. insignis, and A. Jurensis.

B. The Dogger, between the Jurensis-beds and the Macrocephalusbeds, is in North-western Germany divisible into six, perhaps seven members, rather difficult of recognition lithologically, but well marked by fossils. 1. Opalinus-beds, with the following, placed according to their value :-Nucula Hammeri, A. radiosus, Trigonia navis, Cerithium armatum, A. affinis, Astarte complanata, Belemnites Rhenanus, and A. opalinus. 2. The Inoceramus-polyplocus-beds, with I. polyplocus, Gresslya donaciformis, Pholadomya transversa, P. decorata, Goldf. (Zieten?), A. Murchisona, and A. near A. cycloides. The Coronatus-beds, with Belemnites giganteus in both its subdivisions, and with Gresslya abducta, A. Breckenridgii, A. pinguis, A. Gervilli, A. Sauzei, Modiola cuneata, and Belemnites Gingensis in the lower, and Perna isognomonoides and A. Humphriesianus in the upper division. 4. The Parkinsoni-beds. 5. The Ostrea-Knorii-beds, with Rhynchonella varians, Avicula echinata(?), Ostrea Knorii, Astarte pulla, Avicula ferruginea, Belemnites Beyrichi, Trigonia interlævigata, and A. orbis. 7. The ferruginous limestone of the Cornbrash, with Avicula echinata, Echinobrissus clunicularis, A. posterus, and Belemnites hastatus.

C. The Upper Jura, of relatively small extent in North-western Germany, and well opened out by the limestone-quarries, is well known in its subdivisions, of which the author makes ten. 1. The Macrocephalus-beds, with A. macrocephalus, A. Gowerianus, A. funatus, A. calvus, and Pleuromya donacina. 2. The Ornatusclay, with A. cordatus (?), Nucula Pollux, A. Lamberti, A. ornatus, A. Jason, and Gryphaa dilatata (more abundant higher up). 3. The Hersum beds, with Gryphoa dilatata, A. dicatilis, A. cordatus (in lowest part), Belemnites excentralis, A. perarmatus, Modiola bipartita, Lima pectiniformis, A. mendax, and Terebratula Galliennei. 4. The Coral-beds, with Isastrea helianthoides. 5. The Coral-oolite, with Cerithium limaforme, Cidaris florigemma, Rhynchonella pinguis, Pecten varians, Astarte lavis, A. plana, and Lucina aliena. 6. The Nerinæa-Visurgis-beds, with N. Visurgis, Cerithium septemplicatum, C. astartinum, Chemnitzia Bronnii, C. abbreviata, and Astarte scutellata. 7. The Pteroceras-beds, with Terebratula subsella (especially in the higher part), Avicula modiolaris, Lucina substriata, Astarte circularis, Trigonia gibbosa, and Pteroceras Oceani. 8. The Exogyra-virgula-beds, with E. virgula, and Pholadomya acuticosta. 9. The Ammonites-gigas-beds. 10. The Purbeck beds, covering the Portland beds, with, 1st, more than 200 feet of limestone (the Einbeckhäuser Plattenkalk), containing coniferous wood, Corbula inflexa, and a little Estheria; 2nd, the red Purbeck marls, unfossiliferous, and more than 100 feet thick; 3rd, The Serpula-rock ("Serpuli."), about 20 feet thick, made up largely of Serpula coarcervata, and containing teeth of Pycnodus. The true Wealden beds succeed.

General remarks on these groups of strata follow (pp. 61-70); and at page 70 Von Seebach says:-The Hanoverian Jura-formation is in its lower portion, up to the Cornbrash, most like that of South Germany, and was evidently closely connected with it in its origin. Contemporaneously with the formation of the Baltic Jura commenced an approach to the Franco-English type. This similarity holds good for all the Oxfordian Group. The Kimmeridgian Group is in many respects peculiar; but it shows some alliance with that of Northern France. The Purbeck beds are peculiar,

In the Paleontological half of the book (pp. 71 &c.), an extensive table shows the geological distribution, vertical range, and relative abundance of the Liassic, Oolitic, and Purbeck fossils of Hanover, 373 in all-10 Corals, 7 Crinoids, 1 Starfish, 11 Echinoids, 22 Brachiopods, 160 Conchifers, 52 Gasteropods, 188 Cephalopods, 4 Fishes, 4 Reptiles, besides a few Annelids, Crustaceans, Plant-remains, and other obscure fossils.

The last portion of the volume (pp. 85-158) consists of critical remarks on known species (66) and description of new species (25), and is accompanied with ten well-lithographed plates illustrating forty-one old and new species.

[T. R. J.]

ALPHABETICAL INDEX

TO THE

PROCEEDINGS OF THE GEOLOGICAL SOCIETY.

[The fossils referred to are described, and those of which the names are printed
in italics are also figured.]