UNIFORMITY OF CHANGE 



ii 



SUPPOSED ALTERNATE PERIODS OF REPOSE AND DISORDER 

 OBSERVED FACTS IN WHICH THIS DOCTRINE HAS ORIGI- 

 NATED THESE MAY BE EXPLAINED BY SUPPOSING A 

 UNIFORM AND UNINTERRUPTED SERIES OF CHANGES 

 THREE-FOLD CONSIDERATION OF THIS SUBJECT: FIRST, 

 IN REFERENCE TO THE LAWS WHICH GOVERN THE 

 FORMATION OF FOSSILIFEROUS STRATA, AND THE SHIFT- 

 ING OF THE AREAS OF SEDIMENTARY DEPOSITION ; SEC- 

 ONDLY, IN REFERENCE TO THE LIVING CREATION, EX- 

 TINCTION OF SPECIES, AND ORIGIN OF NEW ANIMALS 

 AND PLANTS; THIRDLY, IN REFERENCE TO THE CHANGES 

 PRODUCED IN THE EARTH'S CRUST BY THE CONTINUANCE 

 OF SUBTERRANEAN MOVEMENTS IN CERTAIN AREAS, AND 

 THEIR TRANSFERENCE AFTER LONG PERIODS TO NEW 

 AREAS ON THE COMBINED INFLUENCE OF ALL THESE 

 MODES AND CAUSES OF CHANGE IN PRODUCING BREAKS 

 AND CHASMS IN THE CHAIN OF RECORDS CONCLUDING 

 REMARKS ON THE IDENTITY OF THE ANCIENT AND 

 PRESENT SYSTEM OF TERRESTRIAL CHANGES. 



ORIGIN of the doctrine of alternate periods of repose 

 and disorder. It has been truly observed, that when 

 we arrange the fossiliferous formations in chronolog- 

 ical order, they constitute a broken and defective series of 

 monuments: we pass without any intermediate gradations 

 from systems of strata which are horizontal, to other systems 

 which are highly inclined from rocks of peculiar mineral 

 composition to others which have a character wholly distinct 

 from one assemblage of organic remains to another, in 

 which frequently nearly all the species, and a large part of 



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