MODE I. SIDERITE. 



on the outside appeared of a rust-colour. This 

 is evidently a siderite, of which the iron is de- 

 composed. Fie justly observes, that both must 

 have crystallised together, and of course siderite 

 must be as ancient as granite*. 



The rocks of siderite are by Werner classed 

 among the Primitive Traps, which he divides into 

 the common, the granular, and the schistose; 

 with two mixtures, siderite with felspar and with 

 mica. The admixtion of mica and pyrites is 

 by Daubuisson regarded as characteristic of the 

 primary traps. That of siderite and felspar Primitive trap, 

 constitutes the primitive grunstein of Werner, 

 including the common, the porphyritic, the 

 grunstein porphyry, the green porphyry of the 

 ancients, and grunstein slate ; which latter has, 

 according to Daubuisson, been called horn- 

 schiefer. Some of these primitive traps have 

 been arranged under the large and vague deno- 

 mination of corneennc, roche de corne, pierre de 

 Cornell by the French mineralogists; and even 

 by Saussure, who tells us, 1223, that when the 

 corneenne, or pierre de corne, has marks of crys- 

 tallisation, it assumes the name of hornblende. 

 But as the stones, confessedly called basalts by 



* The summit of the Dome du Goute" consists of siderite in a 

 state of decomposition. Id. 1Q80. 

 f La pierre comic is petrosilex. 



