Notions générales sur l'Écorce terrestre

Abstract

GEOLOGY can be made attractive enough by a good writer who divests the subject of those details which concern only the specialist. To learn the aims of the science and its main results are all that the general reader and the elementary student require; and it is well when, as in the present little work, a distinguished master is not only willing but able to produce such a sketch agreeably written as well as instructive. The subject is introduced in the course of six lessons, and the author, in the first place, deals with the early history of the globe, with seas and continents, and the external features of the earth in general. He passes on to consider various questions of physical geography, and the erosion of the land by rain, rivers, and sea. His remarks on the cutting away of river-courses so as in time to produce a profit d'équilibre are illustrated with reference to the Seine, which has excavated its channel almost to the lowest possible level throughout its main course. The method of accumulation of various sediments, and volcanic phenomena are next discussed. Upheavals and depressions and the sequence of rocks form he subjects of another lesson. Some account of the Paris Basin is given, and in conclusion there is a brief description of the principal geological formations. The work is illustrated by thirty-three figures of fossils, sections, and photographic reproductions. Among the fossils only the principal forms of life are indicated, such as a Sea-urchin from the Chalk, a Devonian Spirifer, Jurassic Ammonites, and a Fossil Bird. The student's mind is therefore not burdened with many names, but a perusal of the work will give him a clear general grasp of the principles and elements of geology. Notions générales sur l'Écorce terrestre. Par M. le Prof. A. De Lapparent. 8vo. Pp. 156. (Paris: Masson et Cie., 1897.)