7© Hints for the Pormat'1071 of a Theory rf the Earth. 



with' a granulated frafture, or the form of a faline marble, 

 and never under a compaft form. 



15. Ought the porphyric fchift of Werner, or the porphyre 

 fchijleux a pate of primitive petrorfilex, to be confidered as 

 primitive or fecondarv ? The fame queition in regard to the 

 mandeljiein or amygdaloid. 



16. Is it fully afcertained, as I thought I obfers'ed in the 

 Alps, and M. de Fichtel in the Carpathian mountains, that 

 there exifts pudding-ftone or free-ftone, if not primitive, at 

 lead of a formation anterior to that of all the other fecondary 

 ftones ? 



17. Were the granites in a mafs firft depofited, becaufe 

 they were lefs foluble? and did they cryftalHfe after the 

 quantity or diflblving force of the waters began to dirhinifli ? 

 and was it for a contrary re?ifon tha,t the gneifs, mica and 

 magncfian ftoncs cryftallifod later ? 



CHAP. xvr. 



Oifcrimtmis to be made on Tranft'icns. 



J. To obfcrve the intermediary genera and fpecles of 

 fofTils, hetweeri one genus or one fpecies of foflil, and the 

 genera and fpecies which have the greateft refemblance to 

 them . 



2. To ohfervc, above all, the tranfitions through \\hich 

 nature has palled, when, having produced one genus or one 

 order of mountains, flic began to produce a diflerent genus or 

 order; for theve is no change of order vvhich has not been 

 the efteA of a revolution ; and it is in the tranfitions that 

 traces of thefe revolutions are tp be found. 



3. Thns we often fee ftrata of free-ftone or pudding-ftone 

 interpofcd between tb.e primitive and fc.condary moimtains; 

 Ircchcs are feen to form the pioft elevated flratum, and con- 

 fequently the neweft of fume calcareous mountains. We 

 muft ftudy then the nature, dimcnilons and pofition of theft; 

 femarkalie ftrata. 



4. Having 



