688 THE JOURNAL OF GEOLOGY. 



Next east of this breccia about six feet of westerly dipping 

 quartzite comes in, constituting the quartzite tongue. South of 

 the Thompson pit this quartzite steadily increases in thickness, 

 and in about 300 feet attains a width of twenty-five feet. The 

 quartzite shows the plainest marks of its sedimentary origin, 

 and it is almost incredible that any other could have been 

 attributed to it. It contains thin layers of conglomerate that 

 may be followed for considerable distances. These layers are 

 composed of nicely rounded pebbles of jasper, of specular and 

 magnetic ore and of quartz, as well as of larger flat slabs of 

 banded jasper. Where the quartzite becomes thicker, a little 

 north of No. 8 shaft, the conglomerate layers in the upper por- 

 tion hold a few pebbles of magnetite-actinolite-schist. In the 

 bedding planes the pebbles have a roughly parallel inclination 

 of 30-40 to the north, which is nearly the general pitch of the 

 trough. A system of parallel normal joints having the same 

 inclination also affects the quartzite as well as the jasper, and 

 seems to have had some influence in localizing ore-concentra- 

 tion, since the small body at the scram immediately north of 

 No. 8 rests upon one of them. 



The quartzite tongue is also in places gashed with a parallel 

 system of narrow quartz veins which dip south about 40°, and 

 so are nearly normal to the pitch. These are confined to the 

 massive quartzite, and stop short at the conglomerate layers in 

 it, nor do they extend into the jasper wedge above or into 

 the main jasper body below. It may be that they represent 

 open spaces where the massive quartzite was pulled apart, pos- 

 sibly at existing joints, by the drag of the upper members along 

 the fault. 



Below the quartzite on the line of section follow three or four 

 feet of conglomerate entirely similar to the conglomerate which 

 overlies the jasper wedge, and having identical unconformable 

 relations with the specular jasper of the Lower Marquette series, 

 which continues in an unbroken body to the east. 



The significant facts along this section (and they are equally 

 evident at many points south), which seem clearly fatal to the 



