ELIZABETHTOWN AND PORT HENRY QUADRANGLES 



41 



CaO.SiOa 



MgO.SiO. 



FeO.SiO^ 



MnO.Si02 ...... 



MgO.Al2O3.SiO2 , 

 FeO.Al2O3.SiO2 . 

 K20.Al203.2Si02 



2MgO.Si02 



2FeO.Si02 



3CaO.Al203.3Si02 

 3Fe0.AL03.3Si02 



2MgO.Si02 



2FeO.Si02 



Magnetite 



Ilmenite 



Apatite 



Pyrrhotite 



H2O— 



Ilmenite 



4.06 



5-90 

 4-88 



6.96 



5-40 



7-13 



.40 



3 



2.90" 



4 10 



5-28 



.66 



1. 41 



1.64 



1.26" 



•56 



.82 



4-50 



Augite 

 ^ and 



'Hypersthene 



:| 



1. 16 



5-46 

 8.36 

 2.Z2 

 6.23 



1-34 

 •35 

 .12 



Biotite 



Garnet 



■87 



1.6s 

 .06 



I 00 



Total 



Light colored minerals. 

 Dark colored minerals- 



100-14 99-80 101.05 



AbiAn2.2 AbiAni.3 AbiAn2 



83-14 55-73 66-36 



17.00 43-95 34.63 



In the quantitative system, nos. i and 3 are both in class II, 

 Dosalane, order 5, Germanase, rang 4, Docalcic, Hessose and sub- 

 rang 3, Persodic, Hessose. No. 2 comes under class III, Salfe- 

 mane, order 5, Gallase, rang 4, Docalcic, Auvergnase, subrang 3, 

 Auvergnose. 



The recasting of no. i presents no difficulties; the calculated 

 results correspond closely with the observed minerals, with the 

 possible reservation that the quartz does not impress one as being 

 so abundant in the slide. No. 2 is also not a difficult analysis to 

 recast and still deal only with observed minerals. The only sur- 

 prising feature is that the relatively small percentage of alumina 

 restricts the possibilities of the anorthite molecule and leads to a 

 variety of plagioclase, AbiAni.3, unexpectedly acidic for so basic 

 a rock. It seems peculiar to have in the most basic of. the three 

 analyses the most acidic feldspar. In no. 3, the slides reveal a 

 complicated mineralogy, since we have both biotite and garnet to 

 deal with, and assumptions are unavoidable in the distribution of 

 certain oxids. Thus there is slight opportunity for error in the 

 pyrrhotite and albite. As regards the others, we are in doubt as to 

 the division of the K^O between the orthoclase and biotite, although 

 it is evident from the slides that the greater part belongs with the 



