i$ A SYSTEM OF 



SECT. XI. 



E. Cryfcallifed calcareous fpars, hops caica- 

 reus cryftallifatus. Spar Drufen *. 



It is compofed of the lad mentioned fpar 

 (Sect.x.), that has formed itfelf exteriorly into 

 ieveral planes or fides, wherefrom many dif- 

 ferent figures arife, the varieties of which 

 have not yet been fully obferved, nor can they 

 be exactly defcribed. The following are there- 

 fore mentioned, only as inftances of the 

 mofr. regular and common kinds, viz. 



i. Tranfparent, Spatum driificum diaphanum, 



a. Hexagonal truncated, Cryftalli fpatofi 

 hexagoni truncati. This is found at the 

 Kartz in Germany, and at Jonufwando 

 in Lapland. 



b. Pyramidal, Pyramidaks. 



1. Dog's-teeth, Pyramidaks dijlinffi. 

 Found at Salberg, and in the iron 

 mines at Dannemera in the province 

 of Upland. 



2. Balls of cryilallifed fpar, Pyr ami- 

 dales concreti-\. 



Thele are balls which have Drufen, 

 pyramidal, oclaedral, fpars accreted 

 in their hollows or centers : they are 

 found at Rettwin in the province of 

 Daiarne, and other places J. 



* Tn my Le&ures on Foffi's I have adopted this German 

 term of Drufen into our Englifh language, for a clufler of re- 

 gular figured bodies, as a Groupe conveys the idea of a clutter 

 only, whether regular or of indeterminate figures. D. C. 



t The concave figured fpar balls in the quarries of Somer- 

 fetihire, and other counties in England. Such balls of free- 

 itone are not unfrequently found. D. C. 



The name ^ipar is very well known, and only ufed to de- 

 termine a certain figure, viz. when a ffcone breaks into a 



rhomboidal 



