262 



ECONOMIC GEOLOGY 



Boone limestones that overlie the base of the Grand Falls chert 

 (Figs. 128 and 129). 



Concerning the genesis of the ore bodies, W. S. Tangier-Smith 

 says: 



FORMATION 



COLUMNAR 

 SECTION 



CHARACTER OF ROCKS 



Cherokee 



-UNCONFORMITY- 



Carterville 



UNCONFORMITY- 



( Short Creek 

 oolite member,) 



Boone 



(Grand Falls 

 chert member.) 



150 + 



Drab to black shale and gray to 

 buff sandstone with occasional 

 beds of coal. 



Light to dark shales and shaly 

 and oolitic limestone with 

 some massive soft to hard 

 sandstones, 



140- 

 485 



(15- 



Massive homogeneous bed of 

 oolitic limestone. 



Limestone, in large part crystal- 

 line, with interbedded chert. 



Heavy -bedded, solid chert. 



T II' I 



FIG. 130. Generalized geologic section of the Joplin, Missouri district. 

 (By permission of the Macmillan Company, from Ries' Economic Geology.) 



"The common association of the lead and zinc ores with the lime- 

 stones, the known occurrence of these metals in sea water, their probable 

 precipitation in minute quantities in limestones laid down in these waters; 

 the actual wide-spread occurrence of lead and zinc in very small amount 

 in the limestones of the Mississippi Valley, both Carboniferous and 

 Cambro-Ordovician, together with the general course of circulation 



