Bibliographical Notices. 175 



the world — except, 1st, that the oldest portion of the record is obscured 

 to a f^reater extent by the change of strata into crystalline rocks, 

 and, 2ndly, the marine formations of the latest period are wanting 

 in this inland region. 



As diti'erent books of historj', having the same basis of facts, vary 

 in their style and appearance, treating the subject-matter broadly or 

 Buccinetly — fomiing a simple plain volume, or appearing with sen- 

 sational pictures and eraltossed l)inding, so the first-mentioned of 

 our natural epitomes of geolr)gy has its leaves and chapters jilain 

 and unl)e(lccko(l, carrying on the student quietly from stage to stage, 

 with but lew outbursts and disturbances of events; whilst the latter, 

 beginning with the results of great changes and bouleversements, has 

 often great events to speak of, fuller scries of events to describe, 

 and l)etter-known communities of life to introduce to notice. 



The mountains, gorges, valleys, lakes, and rivers of ^Switzerland 

 astonish or vaguely interest the mere tourist, give studies of lights, 

 shades, and distances to the artist, offer many problems in physics 

 to the exact inquirer, arid, while presenting difficulty after difficulty 

 to the geologist, at the same time help him to unravel the intricate 

 and solve the doubtful in their structure, and thus open out the 

 succession of events, not only among these crumpled and riven 

 mountains, but in the gradual formation and changes of strata all 

 over the world. 



After the long series of labours carried out by eminent savants, 

 numerous geological sections have been drawn across Switzerland, 

 and excellent maps have been constructed. The more easterly 

 Alpine districts also have been explored and explained by these 

 geologists. Prof. 0. Heer, in the work before us *, illustrates the old 

 geography and hydrography of Central Europe, and its old life- 

 groups, during successive periods, from the Carboniferous to the 

 Quaternary, taking the known stratal conditions and collected 

 fossils as the basis of his animated descriptions and of the pictorial 

 illustrations with which his work is ornamented. 



The oldest and much-altered rocks are known as crystalline and 

 metamorphic, and, although now schistose, gneissic, and granitic, 

 are referable probably to the Devonian, Silurian, and Cambrian 

 systems, if not to the Laurentian also. They form axial masses, 

 longitudinal and otherwise, in many parts of the Alps, having been 

 not only folded but intensely crumpled strata, low-seated, crushed, 

 chemically altered, and ultimately forced to a higher position by 

 the great lateral pressure to which the whole complicated mountain- 

 mass or massif was subsequently subjected. They have been here 

 and there exposed by the destruction of the overriding schists and 

 strata ; and then they stand out as peaks and ridges, or even great 

 rounded bosses, according to their relative hardness, and according 



* The Editor states that the German and French editions were both 

 placed in the hands of W. S. Dallas, Esq., F.L.S., for translation, and 

 that thanks are especially due to that gentleman for the care he has be- 

 stowed on natural -history details. 



