114 HOLLAND: GEOLOGY OF THE NEIGHBOURHOOD' OF SALEM. 



On examining the analyses made of 4 Malabar magnetic ores we 

 obtain similar evidence of the presence of hematite with the magne- 

 tite, and in this case the two minerals are present in about equal 

 quantities. 



Malabar Magnetic Ores. 





Oxides found by analysis. 



Minerals calculated from 

 analysis. 





FeO 



Fe 2 3 



Magnetite. 



(FeO 

 Fe 2 3 .> 



Hematite. 

 iFej 3 .) 



Walluvunad taluk 



Ernad taluk . . • 



Ditto .... 



Ditto .... 



6-67 

 13*91 



6-35 

 14*26 



46*03 

 46*40 



57*37 

 70*34 



21*49 



44-83 

 20*46 



45*94 



30*21 



15*48 

 43*26 

 38*66 







08 



33* 18 





Average 



65 



31*90 



In some cases, as in the ores from Namagiripett, Salem dis- 

 trict, the proportion of hematite is so high that the specimens give a 

 decidedly red streak, and so the presence of hematite can be detected 

 in the field ; in fact this circumstance was noticed when collecting 

 the ores. 1 I have made an attempt to determine the form in which 

 the hematite exists in these ores by etching thin sections with dilute 

 hydrochloric acid. The magnetite dissolved more readily than the 

 hematite, with the result that the residue left by etching gave a dis- 

 tinctly red streak ; but the intergrowth of the two minerals was al- 

 together too intimate to determine in opaque sections their crystallo- 

 graphic relations. The results of the etching, however, leave no 

 doubt that the minerals, besides forming distinct lumps which can be 



1 See Rec, GeoU Surv., Ind. t Vol. XXV, p. 138; and Imperial Institute Hand-book, 

 No. 8, p. 3. 



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