32 BULLETIN OF THE 



which shows the direction and manner of the iipthrust. The point a 

 is at such an elevation that we are not able to assert that it is part 

 of the same formation. It certainly looked the same, and the assist- 

 ant captain in charge of the pit stated that he knew they were the 

 same. The entire mass of jasper and ore represented here had been so 

 acted upon by secondary agencies that it had been mined as " soft hema- 

 tite." In the same pit a beautiful brecciated jasper occurs in which the 

 hematite forms the cementing material (2G9, 270, 271, 272). 



In pit No. 4 a wedge of ore and jasper was seen intruding between 

 and across the lamination of the schist. (Fig. 9.) In the "north pit" 

 the eruptive character of the ore is well shown; Figures 10, 11, and 12 

 showing sections exposed on the walls. Overlj'ing the ore at a low angle 

 is a quartzite containing jasper and ore derived from its underlying ore 

 (277). At the Home mine in the Cascade range the ore was largely 

 a sandstone impregnated with hematite (257), strike N. 70° W. with 

 a northerly dip, which varies owing to the contortion of the strata 

 from 30° to 70°. Several dikes of jasper run through this sandstone, 

 in part conforming to the bending of the strata, and in part breaking 

 across the laminre (258, 259, 260, 2G1). Specimen 259 shows well the 

 contact between the two rocks, the jasper and sandstone, which contact 

 in a less degree is shown by the other specimens. One of these dikes 

 is represented by Figure 13, in which the width is exaggerated compared 

 with the length. There is no mistaking the intrusive character of the 

 jasper and its interlaminated ore here. It is of course almost unneces- 

 sary to state that this mine, having as its chief ore a ferruginous sand- 

 stone, was long since abandoned. The quartzite (metamorphosed sand- 

 stone) which forms the hanging wall of the Pittsbui-g and Lake Superior 

 mine. Cascade range, has been cut through by dikes and little stringers 

 of nearly pure hematite (202, 2G3, 2G4), which in its pi-esent position is 

 distinctly intrusive. While in general these little dikes follow approxi- 

 mately the bedding, they are seen not to exactly do this, but cut the 

 laminae obliquely through much of their course. This mine contains as 

 a secondary formation much specular iron (2G5). Near the bridge over 

 the Palmer mine the jasper shows well its eruptive character in its junc- 

 tion with the quartzite, while the banding is seen to be parallel to the 

 contact line. This jasper holds in it, and as part of itself, the hema- 

 tite mined here. 



It is advocated by Messrs. Credner and Brooks that all the iron was 

 originally in the state of magnetic oxide, this view being sustained by 

 the crvstals of martite found in various parts of the district. 



