176 



because when such a corrugated deposit was first uncovered 

 at Waverley, it looked to the miner like the back or top 

 of barrels lying in rows. 



The slates beds adjacent to the corrugated veins show a 

 sympathetic folding which extends for a few inches to a 

 foot or two from the vein and gradually dies out. Seldom 

 is the influence felt in the quartzite beds ,and then only 

 in connection with the larger corrugations on the apex of 

 an anticline. 



Where one of the corrugations becomes enlarged or some 

 part of a vein swells out and takes on some peculiar form 

 extending for some distance in one direction, this portion 

 of the veins is called a "roll". A roll is generally richer 

 than other parts of the vein. Its position is usually 

 dependent on some peculiarity of rock structure such as 

 some small subordinate crumple, some slight flexure in 

 the beds indicating an incipient crumpling or some zone 

 of fracturing. As such structures usually affect a great 

 thickness of strata, a number of veins is affected by similar 

 conditions and a roll in one vein is succeeded by similar 

 rolls in the underlying or overlying veins. Series of such 

 rolls are found in most districts and constitute one of the 

 principal and more persistent forms of ore deposits. 



Thickness of Interbedded Veins. 



The thickness of the interbedded veins varies from a 

 fraction of an inch to 20 feet (6 m.). The greater number 

 may not be over an inch, (25 cm.) but those that have been 

 worked, generally vary from 3 to 18 inches, (7 to 45 cm.). 

 The largest veins are usually found on sharp anticlines 

 in the shape of saddle veins. Saddle veins attain their 

 maximum thickness at the apex of the fold and become 

 thinner as they extend down on the limbs. Thus the 

 Richardson saddle vein while 20 feet (6 m.), thick at the 

 apex thinned down to 6 feet (1.8 m.) at the 300-foot level. 

 Some leads have been followed in depth several hundred 

 feet with little or no decrease in size, but others have been 

 found to pinch to a mere film and it is probable that nearly 

 all of them pinch out at no great depth. The Dominion 

 lead at Waverley was found to decrease from 15 inches 

 (40 cm.) on the surface to a mere film of quartz with small 

 lenticular pockets at 500 feet (150 m.) and to be completely 

 wanting at 600 feet (180 m.).. 



