84 



ILLUSTRATIONS OF THE 



molt homogeneous bafaltes, to granite the moll 

 highly cryftallized. 



78. Granite, it has been juft faid, exifts moft 

 commonly in malTes ; and thefe maffes are rare- 



, if ever, incumbent on any other rock : they 

 are the bails on which others reft, and feem, for 



moft part, to rife up from under 



or primary ftrata 



The 



g 



therefore 



her ever it is found, is inferior to every other 



ock ; and 





alfo compofes many of the g 



eft mountains, it has the peculiarity of being ele- 

 vated the higheft into the atmofphere, and funk 

 the deepeft under the furface, of all the mineral 

 fubfta^ces vf ith which we are acquainted. 



Notwithftanding the circumftance of not be- 

 ing alternated with ftratified bodies, which 

 conftitutes a remarkable difference between gra- 

 nite and whinftone, the affinity of thefe foffiis is 

 fuch as to make the fimilarity of their origin by 

 no means improbable. Accordingly, in Dr 

 Hutton's theory, granite is regarded as a ftone 

 of more recent formation than the ftrata incum- 

 bent on it ; as a fubftance which has been melt- 

 ed by heat, and which, when forced up from 

 the mineral regions, has elevated the ftrata at ^ 

 the fame time. 



r 



79. That granite has undergone a change from 



is evinced from the cry- 



a fluid to a folid ftate, is evinc 



ftallized ftrudure in which forae of its con^spo- 



neat 





