PALEOZOIC ROCKS FOUND IN DEEP WELLS 



543 



Magnesian group since it has never been discovered in any of the 

 adjacent dolomite formations. In places where the underlying 

 or overlying sandstones are absent this criterion is almost indispen- 

 sable. In northeastern Wisconsin there are pink shaly layers within 

 the Lower Magnesian which can readily be confused with the 



TABLE III 



Partial Log of Well of Peshtigo Pulp and Paper Company, 

 Peshtigo, Wisconsin 



Depth 



(Feet) 



Dolomite, mixed gray and bluish gray 



Dolomite, gray; oolitic chert, gray; specks of blue and green 



shale; caves 



Dolomite, gray; shale, green; sandstone, gray 



Dolomite, gray in part with floating sand grains; shale, blue; 



sandstone, fine, gray 



Dolomite, gray; shale, blue; chert, pink 



Sandstone, coarse to medium, light gray, calcareous 



Sandstone, like above with layers of dark and light gray dolomite 

 Dolomite, dark and light gray, floating sand grains; layers of 



gray calcareous sandstone 



Dolomite, dark and light gray layers 



Dolomite, light gray; chert, oolitic, light gray 



Dolomite, light gray; some sandstone, purplish, red, calcareous. 

 Dolomite, banded purplish red, gray, and green, shaly, sandy. . . 



Sandstone, coarse to medium, light pink, very calcareous 



Dolomite, gray, green, and pink with layers of sandstone like 



above 



Dolomite, light gray 



Dolomite, gray with layers of sandstone and some oolitic chert. . 



Dolomite, gray with much gray chert 



Dolomite, gray with some chert 



Dolomite, coarsely crystalline, gray 



Dolomite, white and gray, chert, gray, both oolitic and dense . . . 

 Dolomite, gray 



Total thickness 



I2S 



I4S 

 1 60 



17s 

 185 

 200 

 205 



210 



252 



25s 

 260 

 265 

 267 



27s 

 285 

 289 

 293 

 31S 

 322 

 326 

 367 



underlying red beds of the Trempealeau. The writer has placed 

 the bottom of the group at the lowest cherty gray dolomite. 



Sandstone beds occur at several levels in the Lower Magnesian 

 group and, except in northwestern Illinois and southwestern 

 Wisconsin, have not been correlated with the formations described 

 above. For the most part the sandstones are relatively coarse 

 grained, light gray or white, and locally contain thin layers of 

 dolomite and less frequently chert pebbles. A white sandstone 



