ELECTRICAL ACTIVITY OF ORE BODIES. 



333 



been partially or wliolly omitted. Instead of i)iving- an outline of the hori- 

 zontal projection of the ore bodies themselve.s, it was thought preferable 

 to represent rather the position and extent of the actual workings. On the 

 map, chamber No. 11 is designated by ah, No. 12 by CD, Nos. 13 and 14 

 by rS, and No. 15 by t(/. The position of chambers Nos. 7 and 10 is only 



Fifi. •27.— Pl.aii of the 400' .nnd .''.nO' levels. Seal 



indicated. Smaller patches of ore also occur at n, between the .iOO and 

 (lOO-foot levels, and at P, above and below the 500-foot level. 



uv, on the 400-foot level, marks the position of a line of contact be- 

 tween shale and limestone. It may be remarked that the shale of the 



