294 THE MARQUETTE lEON-BEARlNa DISTRICT. 



and magnetite these schists pass into the Xegaunee formation. In some 

 cases there are interstratitied typical biotite-schists and griiuerite-magnetite- 

 schists. These biotite-schists are ordinarily, however, strongly gametiferous. 

 The garnet, as usual, developed in large individuals, which include very 

 numerous granules of quartz. Where the garnet appears the biotite is 

 very sparse, so that we have a ramifying background of biotite and quartz, 

 in which are large garnet individuals, including quai-tz and a small amount 

 of biotite. In the schist-conglomerate south of Republic the matrix is a 

 completely crystalline mica-schist, and in their shaj^es and relations to the 

 matrix the mashed granite pebbles are similar to the quartz areas just 

 descrilied. 



relations: to adjacent formations. 



For the part of the l:)elt running from Goose Lake to near Teal Lake 

 the quartzite occupies a place between two slates. It was suggested that the 

 mud of the Wewe slate began to deposit because by the upward building of 

 the limestone the waters became too shallow for limestone formation. A 

 continued sliallowing of the water may have gone on by the upbuilding of 

 the slate until it became so shallow as to permit the waA^es to carry coarse- 

 grained sand, when the sandstone was deposited which was indurated later 

 into the Ajibik quartzite. In places it may be that local elevations occurred, 

 raising the nuid above the water, so that when the waves next overrode it, 

 it yielded fragments of compacted mud to the basal horizon of the quartzite. 

 This is indicated by the fact — discovered by Mr. A. E. Seaman — that in 

 sec. 6, T. 47 N., R. 25 W. (Atlas Sheet XXXVII), south of Carp River, the 

 quartzite, Avith a conglomerate at its base containing slate fragments, rests 

 with slight discordance upon the slate. Also interstratitied with the quartzite 

 for a few feet from the base are thin belts of conglomerate which bear frag- 

 ments of slate identical in character with the slate below. To account for 

 the full thickness of the sandstone, it is supposed that subsidence, if inter- 

 rupted at all, soon began again. After a time it appears tliat the rate of 

 subsidence was greater than the rate of upbuilding, so that following the 

 sand deposits there was another time of mud deposits. Further indicating 

 such a subsidence is the fact that above this shale followed the nonfrao-mental 



