170 



DOMAIN X. TRANSILJENT, 



ing line, in a fragment which has been polished. 

 The porphyry has taken a fine polish, while the 

 basaltin remains dull. The polish of the por- 

 phyry has brought to light little crystals of 

 schorl, or siderite, which could scarcely be dis- 

 covered in the rude fragments.* 



NOME IV. BASALTIN AND WACKEN. 



This transition has also been accurately traced 



by Werner himself. Speaking of the mountain 



Werner's of Scheibenberg, he says, " I have seen there, 



account. . . 



in a successive series of shades, the most perfect 

 transition from clay to wacken, and from this to 

 basalt (basaltin) : these three substances are the 

 produce of the same formation ; that is to say, 

 they are precipitates or sediments of the same 

 dissolution, which becoming more and more 

 quiet, has deposited the clay, then the wacken, 

 and lastly the basalt."f This explanation de- 

 pends upon Werner's theory, that the rocks 

 were deposited by waters in different states of agi- 

 tation or of tranquillity. It may be added, that 

 there is much heat, or, in strict terms, caloric, in 

 water itself, which would otherwise be in a state 



t 



* Jourri. des Mines, iv. 133. f Daub. Basaltes, 58. 



