THE EASTERN AKEA. 



391 



Mingled fragmental ami iiiinfragmental. 



Below is yivcii :i list <if kinds, but even this does not gfive a full idea of the 

 many phases ot rock whirh are almost as nuiiierous as the ledges found, and 

 which if the whole truth were known, would doubtless comprise all possible 

 gradati^ms between the rarities mentioned: 



Quartzites. 



Feldspathie qnartzites. 



Rpoomi)osp(l granite — often conglomeratic. 



Fragmental \ Graywacke. 



Graywaeke-Hlate. • 



Clay slate. 



Sericite-slate. 



Clilorite-slate. 



Ilematitic anil magnetitie ((nartzite. 



Hpmatitic and nia^nctitie graywacke. 



Heraatlte-scliist. 



Hematitic and magnetitic graywacke-slate. 



Forro-doloniitif slate and graywacke. 



Chert-breccia. 



Clierty quartzito. 

 f Chert. 



Noufragmental sediments j Cherty forro-dolomite ^ 



[ Ferro-d(domitic chert. 



The rocks above included among the fragmental sediments are given 

 names which have been before used in the descriptions of the Quartz-slate 

 and Upper slate members in the main Penokee area. These names are 

 here Used with the same significance as before and no characterization need 

 be given of them as a whole. In the tabulations following the rocks 

 are described in detail. The points of general interest shown by the belt 

 are the mingled fragmental and nonfragmental sediments ; the change in 

 the nature of the nonfragmental sediments in following the belt from west 

 to east; and the presence of chert-conglomerates and basal conglomerates 

 at the east end of the belt. 



Mingled fraf/nirntal and nonfrafjmentcd sediments. — The westernmost 

 exposure of the belt is a hematitic schist and cpiartzite in the north part of 

 Sec. 14, T. 47 N., R. 44 W., Michigan. The proportion of iron oxide is so 

 great as to constitute a continuous ramifying liackground in which the frag- 

 mental quartz and feldspar is stuccoed. In no other h'dges of as large size 

 in the belt is the proportion of iron oxide so great. Rocks almost identical 



