370 Analysis of Scientific Books. 



crystalline- rocks, granite, §*c, intumesce, or are forced upwards, 

 either in a solid or fluid state, by the internal expansion; breaking 

 the superincumbent strata, and producing fractures, elevations, 

 and so forth. And when the crystalline rock has passed through 

 the strata, we have granite summits ; and when it has not, why 

 then denudation wears away the strata at the summit, and the 

 crystalline rock becomes exposed just as well as if it had passed 

 through. 



A detailed account of flexures and fissures, and of all the pos- 

 sible and probable modes in which these have been produced, and 

 varied, and modified, is also given ; but those who wish to see 

 how the author has treated all this matter must consult the 

 work ; as whatever appearance of variety in the explanations, as 

 compared to former writers, might appear in consulting the book 

 itself, any abstract of it that we could make would appear a mere 

 repetition of matters a thousand times discussed, and thus, per- 

 haps, diminish whatever credit may be due to the present writer 

 for his industry, ingenuity, language, or whatever else. Simi- 

 larly, it is here shewn, how valleys, as well as ridges, must have 

 been produced by the elevations of the strata, how the retiring 

 waters must have acted on them so as to widen them; and, more- 

 ever, how such waters may have produced valleys, even if there 

 had been no previous channel of this nature prepared for them. 

 And also, the author shews that other valleys have been excavated 

 by the slow action of waters, " among which, the fall of water 

 from the sky, and its abrasive power as it flows over the surface 

 of the land from a higher to a lower level is the principal." 



And here, also, he promises, in a future work, to prove that the 

 quantity of water thus flowing and making valleys is much less 

 now than it was once, and that the waters of the sky or the earth 

 are diminishing ; a theory, however, which is not much newer 

 than what we have already quoted, but of which, nevertheless, we 

 shall be very well pleased to see his new proofs. 



As to the period of these continental elevations and other 

 phenomena, it is left in doubt ; but the author considers that the 

 elevation of the " Colossal European chain, and perhaps, there- 

 fore, of the whole of Europe," " took place at a comparatively 

 recent geological epoch." We do not, however, discover to what 

 the word " comparatively" here alludes, so that, on this head, 

 perhaps the author has not yet completed his investigations. 

 Here also he insinuates in a note, that the elevation of the moun- 

 tains may have had something to do with the near approach of 

 •* an erratic planetary body or comet;" as this would act in a 

 barometrically inverse manner by diminishing attraction, and thus 

 allow the interior rocks to expand. Here also he considers that 

 granite was the u original, or mother rock," converted by cir- 

 cumstances into all others. " A great degree of comminution, 



