1 32 Notices respecting New Booh. 



structure of the earth's surface ; and also of the violent changes 

 and physical revolutions by which it has been disturbed. It has 

 been the object of the author to convey his information through 

 the medium of 40 plates, accompanied by brief descriptions. The 

 number and size of these plates are such as it would have been im- 

 possible to publish at the price affixed to the volume, had they not 

 been almost all lithographed by the author himself. 



Mr. De la Beche appears to have had a twofold object in this 

 work: 1st, to present correct sections and views of the most re- 

 markable geological facts that have been observed in various parts 

 of the world ; 2ndly, to point out the importance of observing ac- 

 curate proportions in these miniature representations of natural 

 pheenomena. He disavows all intention of supporting any theory 

 that has been yet advanced, conceiving that none has yet been 

 published which is competent to solve the many difficult and com- 

 plicated problems presented by geology. But whilst he is the ad- 

 vocate of no theory, he points out the errors and unsoundness 

 of many, especially of that fundamental article of the Huttonian 

 theory, which attributes the excavation of valleys to the action of 

 rain-water and of rivers that now flow through them ; many of his 

 sections represent facts which it is impossible to reconcile with 

 such a theory. In his preface, he quotes from M. Boblaye the case 

 of the valley of the Meuse, showing that if it had cut its own bed, 

 it must have run up hill at least 300 yards to form its present 

 channel through the Ardennes, instead of passing into the basin 

 of the Seine over barriers not exceeding 30 or 40 yards in height. 



The Sections and Views are selected from numerous works 

 through which they are scattered; and in collecting his facts 

 together from these various sources, the author has endeavoured 

 to exhibit their relations to one another, and to the whole earth, 

 and to concentrate their force in pointing towards conclusions 

 which may hereafter be fully established by induction from more 

 numerous particulars. 



Besides the sections derived from other authorities in published 

 works (chiefly the Geological Transactions), the author gives some 

 new and unpublished sections made by himself in different countries. 

 We subjoin one or two examples of his method of showing the 

 value of proportional sections. In Plate 1. are represented two pa- 

 rallel columns, or vertical sections, one showing the thickness of 

 all the strata that occur in Yorkshire, from the chalk descending to 

 the carboniferous limestone (inclusive) ; the other showing the 

 thickness of the same strata in Wilts and Somerset: thus, at once 

 presenting to the eye the relative proportions of the same deposits in 

 the Northern and Southern extremities of England. In PI. 2. he re- 

 presents on a true scale the exact outline of the Alps from the Jura 

 Mountains across the Lake of Geneva, and Mont Blanc to Italy, 

 and contrasts these real representations with the false and carica- 

 tured figures which are usually given in geological sections. A 

 further example of the value of accurate measurement is pointed 

 out in PI. 40 ; where he exhibits the relative proportion which the 



highest 



