64> 



It. is vciy true, this theory lias been taken up by many 

 others, wlio shew an eagerness to express their approbation 

 of it; but not one of them seems to think any further proof 

 of it necessary, than what Mr. Desniarest has ah'eady 

 given. Arguments, therefore, in support of this theor}'', 

 are not to be found in their Avorks, nor, indeed, many 

 facts that apply to the question; but, in their stead, Ave 

 shall find postulates in abundance; for, circumstances most 

 frequently occur, hostile to the volcanic origin of basalt. 

 These must be explained, and accounted for; the friends, 

 therefore, of this opinion, are reduced to the necessity of 

 making postulates, which will, probably, surprise the rea- 

 der, and, I hope, will also afford him some entertainment. 

 I\Ir. Faujas de St. Fond is the most celebrated, as well as 

 the most voluminous writer on the subject. That he con- 

 sidered the volcanic origin of basalt, as a question no 

 longer at issue, but finally decided in the affirmative, ap- 

 pears from the words, with which he commences one of 

 his treatises, " Mineralogie des Volcans." He begins thus: 

 *' Le basalte est une veritable lave, qui a incontestahl''ment 

 " coule." After this debut, the reader will not expect, 

 that Mr. St. Fond will be at the trouble of demonstrating, 

 what he has already taken for granted. An examination, 

 however, of hjs facts is necessary. One of them has been 

 considered, by different writers, as quite conclusive on the 

 question; and, no doubt, at first view, appears to give 

 strong testimony in favour of this theory. 



Mr. 



