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Are its surfaces necessarily parallel tothose of the adjoining rock ? if so, let ushear no more of unconformable and over-Iving stratification.

Is it sufficient that parallelism shall befound in a portion of the rock? Let usnever hear of substances being unstratified.Or must it extend through the entiremass ? Let us hear no more of strata.

The laminae of flagstone, the folia ofslate, are these strata? Are laminae, fourhundred yards thick, strata ? Is thereany assignable limit to their thickness ortenuity ?

When one set of parallel planes crossesanother, are both sets to be called strata, orneither, or only one of them ? If oneonly, by what rule are we to be guidedin distinguishing the real from the counter-feit?

Must the beds be so arranged as to con-vey to the observer the idea of depositionalternately suspended and renewed? Ifthis is not necessary, how is the parallelismderived from stratification, to be distin-guished from parallelism resulting from