GEOLOGY OF IN'OETHEKN WISCONSIIST. 45 



should it be found necessary to do a little testpitting in order to ex- 

 pose representatives of each member of the system. 



A new quartzite locality was discovered on section 6, town 32, 

 range 6, west, during the descent of the Chippewa. It forms a hill 

 about three hundred feet in height, and three or four miles in cir- 

 cumference. The lowest stratum of the formation is reddish met- 

 aniorphic conglomerate, having a thickness of three hundred feet. 

 The pebbles are seldom over an inch in diameter and are either jas- 

 per or amorphous quartz. The matrix consists of reddish grains 

 of quartz. Above the conglomerate is a bed of reddish quartzite 

 four hundred feet thick. The grains of quartz of which the layers 

 are composed are much more distinct than in specimens of quartzite 

 from the Baraboo Hills of Sauk county. Also the rock has a much 

 deeper red color than most of the Sauk county quartz. A depres- 

 sion in the side hill one thousand feet across, comes in above this 

 quartzite upon which exposures were not found. The space is 

 probably occupied by some softer rock than quartzite. Above this 

 arises the main hill of quartzite. In every respect the rock is sim- 

 ilar to that mentioned above. The entire thickness of the forma- 

 tion is not far from five thousand feet. Both the conglomerate 

 and quartzite are distinctly and heavily bedded. The strike is north 

 twelve degrees, west, and the dip sixty degrees to the west. Care- 

 ful observations were taken with the dip compass, and also with 

 the magnetic needle, with a view to discovering magnetic ore de- 

 posits. No undue attraction, however, was observed. 



One and three-quarters miles from the exposures of quartzite, 

 syenitic granites which may be assumed Laurentian in age, were 

 foand in the banks of the Chippewa striking north, fifty degrees 

 east, and dipping high to the north. From the persistency of the 

 strike here and at Little Falls, two miles below, it may be assumed 

 that the quartzites and conglomerates unconforrnably overlie the 

 Laurentian granites and syenites. 



No evidences were observed along the Wolf River, of the crossing 

 of that stream by the Huronian. 



3. Copper-hearing series— The only examinations upon the 

 Copper-Bearing Series during the reconnaissance, were made in 

 the ascent of the St. Croix River. At St. Croix Falls there are sev- 

 eral well defined ridges of Copper-Bearing rocks trending east north 

 east. It is not known, however how far to the eastward they ex- 



