KAOLIN" IX WISCONSIN". 17 



er, in the vicinity of the city of Grand Rapids, in Wood county. 

 The Archaean gneissic rocks here occur chiefly in the bed of the 

 stream, -which for many miles makes bold rapids over their upturned 

 edges. Elsewhere they are mostly covered with sandstone. The 

 predominating gneissic rocks have associated with them both inter- 

 bedded, and clearl}^ intrusive granite and diorite. Of the gneiss and 

 granite there are many varieties, according to the predominance 

 of one or other mineral ingredient, both rocks being formed 

 sometimes of a largely predominating pinkish felspar. These 

 beds are the ones most commonly weathered, though some of the 

 dark micaceous kmds show the same tendency. All of the beds 

 strike between N. 50« E. and N. 80° E. with a dip of about 50« ei- 

 ther S. E. or N. W. 



On the southwest quarter of section 5, town 22, range 6 

 east, on the land of Mr. Garrison, considerable digging has been 

 done in borrowing for the road-bed of the railroad near by. The 

 removal of about two feet of earth has exposed the kaolin in a 

 number of places extending along the railroad for some rods. 

 The clay is here in some places quite white, in others much 

 stained with iron sesquixoyd, the stained portions being those 

 nearest the surface. Much of it appears to have lost all sign of 

 the original rock structure, whilst in many places the spade 

 turned up masses as distinctly laminated as any of the gneiss in the 

 vicinity. All of the kaolin here is quite gritty from the presence 

 of quartz and undecomposed felspar fragments, a statement which 

 will apply to all of the Wisconsin kaolins that have come under my 

 notice. Scales of silvery mica appear to be largely present. Aver- 

 age samples of the whiter clay, selected by the writer, yielded Mr. 

 Sweet, of the State Geological Survey, by whom all the analyses 

 of Wisconsin kaolins quoted in this paper were made, the following 

 results: 



2 W A s 



