Ch. 29] 



LEAD-ZINC REPLACEMENTS 



533 



^1CP ^-V"C <5^° o 



/ ° 1,111,., /' "^-jSS****, °'°^/" 6 '°r, °0 S^"°, 



UJ 



^ ydS?VV»oo °//V°//W/o f 



W° f(( 



° «5% 



/ / 



/" 



7 



§1 



SHAFT N0.12 V V ~ 





^ 



^-6*° 



•NT* / 



•jo o/ 



GRANITE CONTOUR 

 SAND CONTOUR 

 Drill hole, blank 

 Drill hole, ORE 





o / 



°640 'o - 



Scale 



620°" 



500 Feet 



_I I 



(a) 



1,000 -i 

 900- 

 800- 

 700- 

 600- 

 500 J 



Bonne Terre 

 dolomite 



Transition 



Lamotte 



sandstone 



Fig. 1. Ore deposition around a pre-Cambrian granite knob at Doe Run, Mis- 

 souri; (a) plan, (b) section. 



