/. Buskin — Banded and Brecciated Concretions. 



11 



Fio. 1. 



it can. For instanco, Fig. 1 represonts rudely a quartzoso band 



formed at a junction of fluor with siliceous sandstone. The dotted 



space is the grit, 



the un dulating 



lines stand for a 



coarse mass of 



compact fluor 



spar, vaguely 



crystalline in 



that dii'ection. 



The faulting of 

 the band is, I 

 believe, entirely 

 owing to fitful - 

 ness in the cry- 

 stalline action ; 



there is no trace of any kind of flaw or rent, either in the sand- 

 stone on one side, or fluor on the other. 



The composition of the band here, as in the hornstone (GtEOL. Mag. 

 1869, Dec, Fig. 1, p. 529), is of one series of elements only; but very 

 often the chord is composed of a central band, with corresponding 

 opposite series on its sides. Here, in Fig. 2, is a very simple case, 



Fig. 2. 



in which the chord has a thin white central line, with first a dark and 

 then a broader white one oh each side. The entire chord is flung 

 irregularly about the stone, sometimes in continuity for a few folds, 

 sometimes in broken segments ; but the outer white band has the 

 power of detaching itself from the chord occasionally, and of ex- 

 panding here and there into wider spaces. 



And, as in Fig. 1, we have a deceptive semblance of consecutive 

 faults, so here we have an equally deceptive mimicry of brecciation 



