Revieivs — International Geological Congress. 517 



members of the system. The foliation and stratiform appearance, 

 which led the older geologists to class them as altered sediments, 

 is due to movements induced by pressure, and they show protoclastic 

 or cataclastic structure in great perfection. 



To the aqueous rocks, on the other hand, belong the crystalline 

 limestones and certain gneisses usually associated with them. These 

 rocI<:s not only differ in structure from those above referred to, but 

 have a chemical composition not possessed by any igneous rock. 

 The cataclastic structures are very subordinate, and the rocks are 

 characterized by a very extensive recrystallization, accompanied by 

 the development of new minerals. 



It may therefore be said, without going beyond that which the 

 facts warrant, that there are in the Lauren tian at least two distinct 

 sets of foliated rocks. One of these, comprising the limestones, some 

 quartzites, and certain garnetiferous or sillimanite gneisses, repre- 

 sents, in all probability, highly altered and extremely ancient 

 sediments. The other set, intimately associated with these, is of 

 igneous origin, and comprises numerous and very extensive in- 

 trusions, both acid and basic in character, which were probably 

 injected at widely separated times. Those masses which were first 

 intruded, and have been subjected to all the subsequent squeezing 

 and metamorphism, are now represented by well-defined and ap- 

 parently interstratified augen-gneisses and granulites; others, in- 

 truded at later periods, though showing the effects of pressure, 

 retain more or less of their massive character ; while still others, 

 which have been injected since all movements ceased, are recognized 

 by all as undoubted igneous intrusions. 



12, IB 'V' I S "VsT S. 



I, — International Geological Congress. — Congres Geologique 

 International. Compte-Rendu de la Sixieme Session, en Suisse. 

 8vo; pp. xii, 710, with Supplement (Table of Strata). Lausanne, 

 April, 1897. 

 rpHE Sixth Session of the International Geological Congress was 

 _L held at Zurich in 1894, and just before the Seventh Session 

 was held at St. Petersburg, nearly three years after date, the volume 

 of 1894 proceedings was issued. Like the previous volumes 

 published by the Congress, the present work contains a mis- 

 cellaneous series of discussions, reports, and original papers on 

 various geological subjects, together with records of excursions. 

 Most of the articles are in French, but some are in German, and 

 others in English ; and among the subjects dealt with are Ontogeny 

 and Phyllogeny, the structure of gneisses and gabbro. New Zealand 

 glaciers, the geology of Arabia and Palestine, Alpine geology. 

 Contact metamorphism, and Quaternary and Tertiary classification. 

 Perhaps the most important article is that by Professor Renevier 

 entitled " Chronographe Geologique," being an explanatory state- 

 ment to accompan}'- a second edition of his "Tableau des Terrains 

 Sedimentaires," which originally appeared in 1878-4 in the 

 bulletin de la Sociele vaudoise des sciences naturelles, vol. xii, and 



