242 



Lime 0.25 



Majinesia 1.63 



Potash 1.05 



100.00 



No specimen of tbe above lists is without the oxide of iron. In the 

 protoxides, fourteen in number, the percentage ranges from 3.60 to 

 17.60. Of the peroxides, five in number, the per cent, varies from 

 2.16 to 14.40. With one exception, lime pervades the entire list, the 

 proportion in no case attaining to one per cent. Magnesia is present 

 in all but two specimens, the largest amount being 2.80. 



A large portion of formation 3, west of Bad River, is coarsely crys- 

 talline, with a decided sienitic aspect. Around the west end of 

 Bladder Lake it is of a light blue color ; in other places flesh red. 

 Specimens 8 and 9 of fonnation 3 represent this deceptive rock. 



In composition, however, they range themselves with the other 

 specimens of the formation, as substantially silex and iron. Five 

 specimens show potash ranging from 1.45 to 2.66 per cent. 



The absence of potash or soda in two of the trap rocks of formation 

 2, may be accounted for by the fact that in both cases the specimens 

 were porous and exposed to the atmosphere. 



The proportion of caustic alkalies is here much less than in the trap 

 rocks of the same formation on Point Kewenaw, and the traps of 

 other countries. The presence of both potash and soda is a charac- 

 teristic of these rocks elsewhere, and also a much larger per cent, of 

 alumina. In truth, the difference in mechanical condition, as well 

 as chemical constitution, between these beds and those which contain 

 valuable veins, is so great as to discourage us as to their practical 

 value. 



In No. 1 of formation 4, there is found carbonaceous matter like 

 the black slate of the Potsdam sandstone, formation 1. Among the 

 slates of this series there are no instances of the dark green color that 

 characterizes chloritic and magnesian rocks, or which might indicate 

 the presence of silicates of iron. The silex is evidently in excess 

 over all substances that might act as bases, and thus the quartz and 

 iron oxides are proven to be mechanical mixtures. 



There are so many differences between these rocks and those oppo- 

 site them on the southerly side of the granitic f ore of the State, that 

 we should hesitate before we class them together. In tbe azoic slates 

 of the Menominee River, I was unable to determine the stratification, 

 if any exists. Tlie Bad River system is everywhere stratified, and 

 is also conformable throughout. 



On the Menominee there are no intercalations of Potsdam sand- 

 stone, and no beds of trap. On the Bad and Montreal Rivers there 

 are no masses of crystalline limestone. The quartz beds of the Me- 

 nominee are portions of the Potsdam in a compact form. They rest 



