CHAP. VII. 



On the Characters and Forms of Strata, and on 

 Stratification. 



As THE stratified rocks form the far larger portion of 

 the visible solid materials of the earth, we are able the 

 more easily to satisfy ourselves respecting their nature 

 and relations, and to determine, by actual observation, 

 much of that which, in the case of the unstratified 

 substances, is matter of inference from limited facts. 

 If there have been geologists unwilling to admit of the 

 stratification of rocks, there have been others who 

 have seen strata where they had no existence. It is 

 the business of science coldly to investigate truth. 



The term stratum, or bed, carries its own definition 

 with it ; its extent, according to the prolongation of 

 its great opposing planes, being generally far greater 

 than its thickness. A repetition of such beds forms a 

 series of strata ; and the term stratification implies the 

 mode of their deposition, to whatever cause that may 

 be attributed. Such masses, of analogous or similar 

 shape, as are occasionally found among the rocks 

 described in the tenth chapter, are however excluded 

 from this definition. Their origin and forms are 

 attributed, from the evidence elsewhere stated, to a 

 different cause ; and the mode of distinguishing them 

 is also specified in its proper place. The term stra- 

 tification therefore implies a cause, as well as a mode 

 of form and disposition ; and that cause is assumed, 

 or proved, to consist in a deposition from water, of 

 materials that have been suspended and dissolved in it. 



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