Report of U S. National Museum, 1899. Merril 



PLATE 10. 



IDEAL SECTIONS SHOWING THE FORMATION OF MANGANESE-BEARING 



CLAY FROM THE DECAY OF THE ST.CLAIR LIMESTONE. 



MANGANE SE-BEARING CLAY LZulZARD LIMESTONE 



ED SACCHAROIDAL SANDSTONE 



sdBooNE CHERT 

 I - i -'-'\ ST.CLAIR LIMESTONE: 



FIG.I. ORIGINAL CONDITION OF THE ROCKS. 







1,1 



FIG. 2. FIRST STAGE OF DECOMPOSITION. 



FIG.3. SECOND STAGET OF DECOMPOSITION. 



FIG. 4. THIRD STA8E OF DECOMPOSITION. 



SECTION SHOWING THE FORMATION OF MANGANESE DEPOSITS FROM DECAY OF 



LIMESTONE. 

 After Penrose, Animal Report Geological Survey of Arkansas, I, 1K90. 



