=.tl 



l\ 



it 



atic 



es 



^k. 





] 





:s 





ler re^'- 



i 



then, I: 

 :biii5: 



1 



oneifi 



Eas^i- 



own f- 



g 



.-^ 



,t^ 



lieiB/" 



( 



A 



01 



fjtK^ 



fr 



cao"' 



^. 



HUTTONIAN THEORY. 



263 



not mean to faj, that there are among thefe 

 hills no velliges of volcanic explolion. I am 



\ 



very far from having data fafficient for drawing 

 this conclufion ; but I believe it may be fafely 

 affirmed, that the bulk of them is no more com- 

 pofed of volcanic lava, than the bafaltes of StafFa, 

 or of the Giant's Caufeway. 



236. But, befides the evidence deduced from 

 calcareous fpar and zeolite, againil the rocks 

 containing them being real lava, there are other 

 marks, even lefs equivocal perhaps, that diftin- 



A 1 



guiOi the lavas which we fuppofe to have flow- 

 ed in the mineral regions, from thofe which 

 have adtually flowed on the furface. Thefe are 

 what we collect from the difpofition, the orga- 

 nization, or, as we may fay, the pliyfical geogra- 

 phy of whinft:one countries, unlike, in fo many re- 

 fpeds, to that of volcanic countries. The fliape 

 of whinfl:one hills ; their large flat terraces, riling 

 one above another ; their perpendicular faces, 

 and the correfpondence of their heights even at 

 coniiderable diitances ; have nothing fimilar to 

 them in the irregular torrents of volcanic lavas. 

 The phenomena of the former are alfo on a fcale 

 magnitude very far exceeding the latter, and 

 clearly indicate, that though both have been 

 produced by fire, it has been by fire in very dif- 

 ferent circumfl:ances, and regulated by very dif- 

 ferent laws. The ilrudure of the two kinds of 



of 



R4 



rock 



* 



/ 



