THE ninth gathering of the International Geological Congress was held this year in Vienna. After a preliminary series of excursions through different parts of. Austria-Hungary the members assembled in the rooms of the University on Thursday, August 20, when the meeting was inaugurated by the Archduke Rainer and the Minister of Public Instruction. According to the programme prepared by the committee of organisation, each alternate day was to be devoted to the reading and discussion of papers on given subjects of general interest, while the intervening days were given up to excursions in the neighbourhood of the imperial city. After the formal opening Of the congress, the afternoon of the first day was spent, under the presidency of Mr. Emmons, of the United States Geological Survey, in receiving a miscellaneous group of communications, including a paper on the Laccolites of the Aar-massif by Prof. Baltzer, and an account of the recent volcanic eruptions of Martinique and St. Vincent by Mr. E. O. Hovey, illustrated by an excellent series of photographic lantern slides. The next day of discussion (August 22) was dedicated to the crystalline schists, under the chairmanship of Prof. Zirkel in the morning and Prof. Loewinson-Lessing in the afternoon. Until the various communications are in print and can be studied and compared, it is hardly possible to say how far they have advanced our knowledge of the subject. The speakers on this and subsequently on the other selected subjects of discussion showed a prevailing tendency to dwell on the local peculiarities of the regions most familiar to them, and rather to lose sight of the general principles to which local observations should properly lead. The crystalline schists of Germany, Austria, the Alps, Finland and North America were all brought into review, so that a sufficiently wide basis was provided for satisfactory generalisation. The third day (August 24) for the reading of papers, under the presidency of Sir Archibald Geikie in the forenoon and Prof. Heim in the afternoon, was spent in listening to essays by various geologists on the important phenomena embraced under the general designation of “overthrusts.” MM. Lugeon and Hsug described the structures displayed in the Alps, Prof. Uhlig those of the Carpathians, Mr. Bailey Willis those of the United States. In an interesting discussion Prof. Heim indicated that he surrendered the so-called “double-fold”of the Glärnish, as originally advocated by him, and now admitted that the structure implied a gigantic over-thrust. Prof. Rothpletz, who has long maintained this view, also took part in the debate, which at times became lively from the energy of the speakers and the difficulty which they found in confining their exuberance within the limits of time prescribed by the council. Though the doctrine of overthrusts was admitted, considerable divergence of opinion appeared as to the true nature and origin of the structure.