DOMAIN I. SIDEROUS. 



6f the ancients was more commonly of a coarse 

 grain, and often intermixed with quartz or fel- 

 spar, it has been thought proper, for the sake of 

 precision, to confine the term to that substance ; 

 while the name basal tin is applied to the fine- 

 grained basalt of the moderns, which frequently 

 assumes the columnar form, in which shape also 

 the former sometimes occurs. There is no doubt, 

 for example, that some of the whins of the Scot- 

 ish mineralogists, in which grains of quartz or 

 felspar are mixed with trap, strictly and properly 

 belong to the basalts of the ancients. 



The dispute therefore concerning the Nep- 

 tunian or the Volcanic origin of this substance 

 must more aptly be considered as having no 

 concern with the proper BASALT of the ancients, 

 but with the modern basalt, here called basaltin. 

 The author of this work is not attached to any 

 theory, nor does he believe that the facts and 

 observations are yet sufficiently numerous to 

 afford even the semblance of a plausible conca- 

 tenation j but he may be allowed to observe, that 

 though volcanoes are often situated in basaltic 

 countries, as they of course abound with iron, of 

 itself inflammable, and yet more with sulphur, 

 and probably forming the great source of vol- 

 canic fires ; yet, as there is no proof of any vol- 

 cano, however vast and powerful, as Etna, or 



