ADIRONDACK MAGNETIC IRON ORES 



163 



already been noted. The ores which have anorthosite for walls 

 are more uniform than the others in their physical appearance and 

 mineralogy, and also appear to be somewhat richer in iron. As 

 a rule they are coarsely textured ; the constituent grains of magne- 

 tite have a mean diameter of J to J inch. When free from feldspar 

 they can scarcely be distinguished in hand specimens from the 

 nontitaniferous magnetites. Variations in granularity can be 

 noticed in different parts of the same ore body, but the grain 

 seldom approaches the fineness of the ores included by the gabbro. 

 With the exception of inclusions of labradorite and occasional 

 crystals of pyroxene, they are remarkably pure ores. The ores 

 found in the gabbro usually carry these minerals in quantity, as 

 well as garnet and small amounts of pyrite and apatite. Their 

 texture approaches that of a normal gabbro, owing to the presence 

 of the silicates, and they are very dense and tough. 



The following analyses furnish particulars as to the chemical 

 composition of the ores from the principal deposits. They have 

 been obtained from the papers by Kemp and Rossi, except Nos. 5 

 and 11 which have been communicated by Mr W. L. Cumings and 

 No. 6 which was made by Prof. E. W. Morley from a sample gathered 

 by the writer. 



Sanford deposit 

 3 



Fe 3 4 ... 



.. 70.80 



7i-o3 



70-73 



87.60 



Si0 2 



.. 1.39 



i-34 



2 .46 



.87 



Ti0 2 .... 



.. 19.52 



18.70 



20.03 



IO.9I 



A1 2 3 ... 



4 . 00 





3-50 



•S3 



P 



.022 









S 



.028 









Iron 



•• 5!-3o 



5*-44 



51.22 



62.65 







Mill pond pit 





Cb 



2 



09 



9 



45 





007 





027 



6 

 083. 4 



14. 



63-36 



Fe 3 4 . 

 Si0 2 .. 

 Ti0 2 .. 

 A1 2 3 . 

 P.... 

 S 



87.20 

 1 .09 



10.73 

 .44 

 nil 

 nil 



8 

 82.37 

 3-67 

 13.38 

 I.50 

 .OI7 

 .068 



73 

 1 



3 



62 



53 

 74 

 5o 



037 

 08 



86 



Cheney pit 

 10 

 55-64 



9-79 



15-77 

 7. 12 



1 .00 



53 



25 



39 

 74 



60.5 



Iron dam 



12 



I .96 



IO.85 



.008 

 .OO9 



Iron, 



63-45 59-56 53-62 40.33 62.15 64.47 



a Fe 2 3 55.9; FeO 27.5. 



