256 ACCOUNT OF THE MINERALOGY 



covering the summits and sides of this cone, excepting on the 

 south, a bed of greenstone stretches, which is rendered parti- 

 cularly conspicuous by the vertical rents of its prismatic con- 

 cretions. On the west side, after descending more than half- 

 way from the top of the cone mentioned, it continues towards, 

 and again rises to the top of Dalsnypen ; from whence passing 

 under other beds, it may be traced in an undulated line, al- 

 most without interruption, to Skellingfeld, where it terminates 

 in a wedge, about half-way from the base of that hill. A little 

 north of this, and nearly in a line, the same kind of greenstone 

 recommences, and extends to beyond Leynum. Skeeling pre- 

 sents on the west side a bare section, like the conical hill of 

 Norderdahl, whence the beds may be counted in one continu- 

 ous slope, from the base to the summit, rising to a height of 

 about three thousand feet ; and Tiere, although the powerful 

 mass of greenstone I have just noticed, loses itself in a wedge, 

 there is not the slightest derangement created among the other 

 beds of trap of which Skeelingfeld is composed. 



The position of this enormous mass of greenstone is worthy 

 of attention, and is difficult to reconcile with any of the doc- 

 trines I know of. Its occurrence in Skeeling, &c. as an adven- 

 titious bed, like that of Salisbury Craig, is nothing uncom- 

 mon ; but when it extends from under the incumbent trap, 

 stretching itself over a most irregular surface, and finally co- 

 vering, as hke a cap, a very acutely conical hill, it assumes a 

 new and totally different character. 



It is in the beds of amygdaloid that the beautiful zeolites 

 and calcedonies are found. I have already noted the different 

 places where they occur, and have also given sufficient details 

 respecting the varieties of zeolite. But as the peculiarities of 

 Calcedony have often been urged in support of doctrines very 



opposite 



