07 CHAP. VII. On (lie Characters and Forms of Strata, and o>, Stratification. As the stratified rocks form the far larger portion ot 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. F 2