64 GEOLOGY OF MOOSE RIVER GOLD DISTRICT — WOODMAN. 



parallel to it. It dies out completely before reaching the surface. 

 The lamiiifB of slate close to the lead curve with it, but the 

 general stratification is unchanged (pi. 11, fig. c). 



In shape, the crinkling varies from broad open folds to close 

 and overturned ones. The latter, in inclined strata, are over- 

 turned uphill, as in pi. 13. The curves may or may not be 

 rhythmic. When even in interval they usually are uniform in 

 amplitude. When uneven in either way, there often is some 

 •sj'Stem in their irregularity, a rhythmic change such as in pi. 11, 

 figs, e, f, being common. In a larger way most of the leads 

 show the same thing. Thus the Jo. Taylor, especially the foot- 

 wall lead in the quarry on areas 73 and 74, is corrugated evenly 

 and steadily for many feet across the strike. Those show it 

 best, perhaps, that lie in belts bounded on one or both sides by 

 whin. Here the veins are crenulated strongly, the size of the 

 folds being still proportional to the breadth of quartz. The 

 sharpness of curvature is inversely as the thickness of the veins. 

 In these cases the slate is folded to a thickness depending upon 

 the size of the vein and violence of its contortion, and the prox- 

 imity of whin. Sympathetic folding of the countr}^ rock rarely 

 extends more than two feet away from the lead, on either side. 

 If whin bounds the belt within the distance to which this fold- 

 ing would tend to extend, the latter is arrested, never affecting 

 the whin. When, as often happens, the lead lies along one wall 

 of the belt, the adjacent whin prevents rolling of the strata on 

 that side. It is never strictly true, however, that the vein lies 

 next the wall. A thin band or rind of slate intervenes, and is 

 frequently closely folded, slickensided and crushed by the intense 

 strains to which it has been subjected. This is not especially 

 well shown at Moose River, because whin walls are rare. 



Crenulations : Kaulhach belt of angidars. — A special case 

 is found in that class of angulars which run parallel to the 

 strike of the strata, but break across the dip. Sone belts are 

 composed entirely of a network of such veins, instead of having 

 bedded leads. In these instances the belt as a whole follows the 



