THE UrPEK MARQUETTE SERIES. 409 



SECTION I.— THE ISHPEMING FOESIATIOK. 



By C. R. Van Hise. 



The Ishpemiug formation is so named because typical exposures of 

 this formation surround the city of Ishpeming- and underhe it. For the 

 eastern part of the district, and including the Ishpeming area, the predomi- 

 nant rocks are conglomeratic quartzites and quartzites. These are finely 

 exposed at and adjacent to the Goodrich mine (Atlas Sheet XXYl), and 

 this rock will therefore be called the Goodrich quartzite. In the western 

 part of the district, Avhile quartzites are present, a peculiar schist, which is 

 typically exposed at the lower part of the Bijiki River (Atlas Sheet VIII) 

 and will therefore be called the Bijiki schist, occupies a large part of the 

 horizon of the Goodrich quartzite and is equivalent to it in age. 



THE GOODRICH QUARTZITE. 



DISTRIBUTION, EXPOSURES, AND TOPOGRAPHY. 



The easternmost occun-ence of the Goodrich quartzite is the Palmer 

 area (Atlas Sheet IV). From the village of Palmer it extends east and west 

 about 1 i miles, making a belt 3 miles long. From near its center, as a 

 consequence of subordinate folding, a short belt projects to the southeast. 

 Small isolated patches may also occur capping the Ajibik quartzite of the 

 Ajibik Hills. The second subordinate area is near the town of Negaunee, 

 north of the Jackson mine. On account of the close folding the boundary 

 line of this area is very in-egular. The chief area, as has been said, Begins 

 at Ishpeming. From this area a rather naiTow belt extends, in a course 

 nearly due west, to west of Michigamme. Another arm, of irregular width, 

 swings to the south and southwest, then follows a general westerly course 

 to sec. 20, T. 47 N., R. 28 W., where it swings to the northwest to Hum- 

 boldt and Champion; thence it extends west, southwest, and south to the 

 end of the Republic tongue, in sec. 7, T. 46 N., R. 29 W., passes around 

 the end of this tongue, and again swings to the northwest to sec. 20, T. 47 N., 

 R. 30 W.; thence it swings to the west and south, beyond the limits of 

 the district. West of this belt is still another. 



