156 



generally group in greater numbers and with less regularity, 

 thus forming the Cock'scomb Pyrites above referred to in 

 tab. 366. The crystals are much elongated, and some of 

 them are joined by their convex faces, forming deeply fur- 

 rowed groups, not notched plates. 



The gangue of this specimen is octaedral Galaena coated 

 by Cubic Fluor. 



TAB. CCCLXXXIV. 



JThis is a modification depending on the same laws of 

 aggregation as the last; but the notches are filled up by a 

 continuation of the striated faces : the crystals are much 

 compressed, and often very thin, having the appearance of 

 hexangular plates, three sides of which stick deep in the 

 gangue: they however terminate more or less solid in two 

 or three angles only, against each other, or in the more 

 massy part of the Pyrites. This Pyrites alternates two os 

 three times with the Ouartz. 



