MODE II. BASALT. 



some of those in the Andes, having in any anr 

 cient or modern eruption furnished basalt, either 

 in columns or in strata, it would seem an infal- 

 lible inference that this substance cannot be of 

 volcanic origin*. The wide extent also of this 

 substance, and the common situation of basaltic 

 columns on the summits of hills, strongly mili- 

 tate agains.t this idea. The same formation of 

 basaltic columns resting sometimes on amor- 

 phous basalt, sometimes on indurated clay tinged 

 with red ochre f of iron, is found to extend near 

 thirty miles into Ireland from the Giants' Causy, 

 and as far as the northern Faroe isles, a space 

 of more than six degrees, or three hundred 

 and sixty geographical miles ; and, it is worth 

 remarking, nearly in the same meridian. In 

 like manner the basalt of Saxony might be said 

 by a theorist to extend through Sweden, even to 

 Spitzbergen; and it is observable that all the 

 northern parts of Europe abound with iron ; 

 those of Asia are concealed by perpetual ice, 

 snow, and marshes; while those of America 



* None of the numerous hills around Etna is capped with 

 basalt ; nor have the isles ejected by submarine volcanoes presented 

 that substance; so there is no proof of a subaqueous origin. The 

 .prisms on the shore around Etna are very rude, and unlike the 

 beauty and exactness of basaltic columns. 



t Does the red colour indicate heat, as yellow ochre thus asr 

 /sumes that tinge ? 



