270 THE PENOKEE IRON BEARING SERIES. 



It is not meant to imply that the more numerous cUiss of deposits 

 which have been spoken of as resting upon the foot-wall quartzite liave 

 the clean ore always in contact with it. Quite often there is a layer of 

 what the miners denominate "paint rock," or a layer of sand rock between 

 the quartzite and the ore. This latter material is sometimes as nmch as 20 

 feet in thickness, although it is usually not more than a few inches, or at 

 most a few feet. The sand rock here found is so friable as to readily crumble 

 between the fingers; in fact, is no more than coarse sand. The paint rock, 

 a commoner mateiial, is a soft red substance, rich in iron, at times carry- 

 ing more than 50 per cent. It appears like a heavily ferruginous clay, and 

 varies in thickness from a mere film up to 5 feet. Sometimes, also, there 

 is between the ore and the quartzite a mass of greater or lesser thickness of 

 the ferruginous cliert or "mixed ore" of the miners. Rarely a thin layer 

 of nearly pure w!iite chert is found between the ore and quartzite. Not- 

 withstanding all these exceptions the south side of the ore never penetrates 

 the quartzite and ra a general way follows it, so that it may be spoken of 

 as resting upon it. It will be remembered that this quartzite has an aver- 

 age dip to the north of from 60° to 70°, and it thus furnishes an approxi- 

 mately regular wall, north of which the ore lies, and is conseqviently 

 always called the foot wall by the miners. While it is true that the aver- 

 age dip of this quartzite is as given, it has subordinate irregularities as 

 great as the ordinary eroded surface of a gently uudulatory country. In 

 shafts which follow it the dip is at times as high as 75° or 80°, while in 

 other places it is not more than 45°. Also in horizontal drifts which are 

 following the quartzite this same v;ndulatory character is seen. For 

 instance, one such drift in the Colby mine in following the quartzite bows 

 sharply at one place and runs almost due south for some feet before strik- 

 ing the quartzite, although it has just before been alongside of it. 



The so-called "north vein" deposits are described by Mr. J. Parke 

 Channing as always having regular south walls, which dip with the forma- 

 tion and are called by the miners "foot walls." Such walls niay be well 

 seen at the open pits of the Montreal, Mount Hope, and Colby mines. 



The diff'erences between the foot walls (of the so-called north veins) 

 and the southern deposits will be later considered. For the present it is suffi- 



