124 DOMAIN I. SIDEROUS. 



In very thin plates, and of an almost impal- 

 pable grain, from Scotland. 



Brown mica slate, from the same countries. 

 The green and white need not be here specified. 



STRUCTURE II. IRREGULAR. 



if 



The noted hornberg of the Swedes belongs to 

 this division, being a coarse mica slate irregularly 

 contorted. It is very metalliferous *. As it is a 

 celebrated rock with a barbarous appellation, it 

 may be called Linnite, in honour of Linnaeus, a 

 native of Sweden, who however contributed but 

 little to its mineralogy. 



Linnite, from Sweden. 



The same, from Norway. 



STRUCTURE III. MINGLED. 



When mica slate is mingled with garnets, it 

 constitutes the Murkstein, orNorka, of the Swedes, 

 and the latter name might be retained, if requisite; 

 but garnets form so common an adjunct of mica 

 slate, that the distinction seems unnecessary. 



Mica slate, with garnets, from innumerable 

 countries. 



* See Journal des Mmes > No. 88, p. 257. It is granular, black- 

 ish, with thick and short layers. 



