84 Reviews — Geologie pour ies Annies 1876 et 1877. 



ing nebulae ; they do not contain the spectra of all the known 

 elements, and hence it might be inferred that none of them could 

 condense into a system like ours. To this, Mr. Skertchly replies 

 that, " It may be that at excessively high temperatures most of the 

 vibrations are too rapid to emit light, and hence, even if our 

 elements are truly such, they might fail to yield a spectrum under 

 nebular conditions." 



In concluding this outline of Mr. Skertchly's work, we cannot 

 refrain from complimenting him upon the care he has bestowed upon 

 this subject, and from expressing our belief that he has formed a 

 very solid nucleus from the nebulous matter that is scattered through 

 a wide range of knowledge. H. B. W. 



II. — Eevue de Geologie pour les Annees 1876 et 1877. Par 

 M. Delesse et M. De Lapparent. (Paris : P. Savy, 1879.) 



THE onward progress of geology is fully evidenced by the 

 numerous works which of late years have been published 

 bearing on that science. Distributed as separate treatises, or as 

 memoirs and papers in various scientific journals, or in proceedings 

 of societies, and in different languages — the majority of them might 

 be comparatively unknown to many geologists, without some general 

 record of their place of publication. This desideratum has been 

 fulfilled by the "Eevue de Geologie" of MM. Delesse and De 

 Lapparent, of which fifteen volumes have now appeared, and to 

 which object the " Geological Eecord " and " Eevue Geologique 

 Suisse " have also contributed. With the fifteenth volume of the 

 "Eevue de Geologie," the Editors have brought their French record 

 of geological literature up to 1877. Commencing in 1860, the series 

 now published contains a vast amount of useful information with 

 regard to the various publications issued during the period, and so 

 arranged as to be easily referred to. The subjects in this, as in the 

 preceding nine volumes, are classed under the chief divisions adopted 

 by Prof. Dana in his Manual of Geology, — physiographical, litho- 

 logioal, historical, geographical, and dynamical geology. As in 

 preceding years, the authors have endeavoured to present a concise 

 but faithful and methodical analysis of the various memoirs which 

 have contributed to the advancement of geological science during 

 the years 1876-77. J. M. 



III. — Contributions to the Knowledge of the Eruptive Eocks 



in the District of Saar and Moselle. — "Beitrage zur Kentniss 



der Eruptivgesteine im Gebiete von Saar und Mosel." 



Von Prof. Dr. A. von Lasaulx. pp. 76, with 2 coloured plates. 



(Bonn, 1878.) 



N this treatise the author describes the mode of occurrence, the 



megascopic, and the microscopic characters of a number of 



eruptive rocks which have hitherto been, with a few exceptions, 



designated Greenstones. The rock first described is the Diabase- 



Diorite of Kiirenz, near Trier. Then follow descriptions of an 



