208 



THE GKYSTAL FALLS IRON-BEARING DISTRICT. 



adixoi.es. 



C'hloi-ite has been the chief dark mineral in the contact products thus 

 far uK^ntioned, with actinolite as an accessory. In the adinoles actinohte is 

 the characteristic constituent. The mineral constituents in the adinoles are, 

 as a rule, more uniformly distributed than is the case with the spilosites; 

 however, the spots are composed essentially of actinolite. The actinolite is 

 in sheaf-like growths. These actinolite sheaves lie in an exceedingly fine 

 grained mass of quartz and albite, with some flakes of chlorite and grains 

 of epidote. The groundmass is formed of such minute mineral constituents 

 that no conclusive test could be obtained for the determination of the 

 limpid grains, and their nature has been concluded from the analyses. The 

 rock is rendered rather dark by minute black specks dissemhiated through 

 it. In places these are collected in irregular or lenticular heaps. They 

 seem to be carbonaceous matter. 



Analyses of adinoles. — TliB followlug is au aualysls (No. I) by Mr. George 

 Steiger, of the United States Gleological Survey, of one of the typical 

 adinoles from this district. With this there are given for comparison two 

 adinole analyses (Nos. II and III) by E. Kayser.^ 



Analyses of adinoles. 



SiO.> 



TiO. 



AliOs 



FejOs 



FeO 



MnO 



CaO 



BaO 



MgO 



K..0 



Na,0 



H.2O at 100^' — . 

 H.2O at lOO-^ + . 



PiOft 



CO, 



FeS2 



C 



Total 



74.16 



.37 



11.8.5 



.82 



1.66 



.06 



2.10 



None. 



2.10 



.15 



6.57 



.05 



75.25 



11.80 . 15.81 



Trace. ' — 



1.76 .74 



32 



1.02 



1.57 



.61 



7.54 



.81 



8.33 

 .61 



I E. Kayser, Zirkel, Vol. II, p. 721, Analyses III and VI. 



