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pute relative to the origin of bafaltes is at 

 an end ; nor would there be any difference 

 of opinion if, inftead of generalizing ideas 

 and fabricating fyftems, naturallfts would 

 make an impartial ufe of their own obfef va- 

 tlons and thofe of others. Some volcanlfts, 

 perceiving that the generation of various 

 bafaltes is evidently igneous, have immedi- 

 ately inferred that all muft have the fame 

 origin. In confequ^nce of this principle, 

 they have drawn lines or zones, in different 

 parts of the globe, indicative of extln(St vol- 

 canos, which they have inferred from find- 

 ing bafaltes there ; and thus pourtrayed a 

 pidure of prodigious dimenfions, repre- 

 fenting the ruins caufed in the world by 

 fubterranean conflagrations. Other natu- 

 rallfts, on the contrary, being convinced 

 that certain bafaltes are the produce of 

 w^ater, have affigned to all the fame origin. 

 From the fad:s now adduced, it is, however, 

 fufficiently evident that both thefe hypothe- 

 fes are erroneous. The bafaltes, taking 

 the term generally, when examined de- 

 tached, do not bear exclufively any declfive 

 O 4 marks 



