4i6 On the Absence of paet h. 



faults and dislocations, — by inland lines of escarpments, 

 by outliers, and numberless other facts, and by that 

 argument of high generality advanced by Mr. Lyell, 

 namely, that every sedimentary formation, whatever its 

 thickness may be, and over however many hundred 

 square miles it may extend, is the result and the measure 

 of an equal amount of wear and tear of pre-existing 

 formations; considering these facts, we must conclude 

 that, as an ordinary rule, a formation to resist such vast 

 destroying powers, and to last to a distant epoch, must 

 be of wide extent, and either in itself, or together with 

 superincumbent strata, be of great thickness. In this 

 discussion, we are considering only formations contain- 

 ing the remains of marine animals, which, as before 

 mentioned, live, with some exceptions, within (most of 

 them much within) depths of a hundred fathoms. How, 

 then, can a thick and widely extended formation be 

 accumulated, which shall include such organic remains ? 

 First, let us take the case of the bed of the sea long re- 

 maining at a stationary level : under these circumstances 

 it is evident that conchiferous strata can accumulate 

 only to the same thickness with the depth at which 

 the shells can live ; on gently inclined coasts alone can 

 they accumulate to any considerable width ; and from 

 the want of superincumbent pressure, it is probable 

 that the sedimentary matter will seldom be much con- 

 solidated : such formations have no very good chance, 

 when in the course of time they are upraised, of long 

 resisting the powers of denudation. The chance will 

 be less if the submarine surface, instead of having re- 

 mained stationary, shall have gone on slowly rising 

 during the deposition of the strata, for in this case their 

 total darkness must be less, and each part, before being 

 consolidated or thickly covered up by superincumbent 

 matter, will have had successively to pass through the 



