Art. IX.] Watson, Manganese Ore- Deposits of Georgia, 189 



haustive and excellent volume on manganese.' The only point 

 of difference between Prof. Penrose and myself, as to the Geor- 

 gia ores, is that of the occurrence of some of the ore-bodies in 

 the residual clays occupying similar positions in the original 

 fresh rock, as stated by Penrose. The writer has not ob- 

 served a single occurrence of the ores in the fresh rock in the 

 Georgia area. 



II. Manganese-Deposits of the Crystalline Area. 



The position of the Crystalline area is shown on the accom- 

 panying map (Fig. i). The area includes two physiographically 

 distinct provinces, namely, the Appalachian mountains and the 

 Piedmont plateau. The transition in the rocks of the plateau, 

 along its northwest margin, to those of the mountain province 



Fig. 19. 



> •»•♦ .".41 •:•:;•••.!• .\vv;- ..••,•.••.*••:.•• 

 ■■'^.■:^:.'---:^.i:-\-x^ \v.»-f;^v*-:- ••'••'^ •■••;'•••• •■•••^*. 



Section along the South Face of the Large Opening on the Lowe Tract, 

 near Cave Spring, Floyd Co., Georgia, Showing the Occurrence of Manganese 

 "Pellet"-Ore in the Residual Clay. 



Black dots indicate the "pellet"-ore ; white areas, deep red-brown clay de- 

 rived from the Knox dolomite. No admixed chert-fragments or nodular ore 

 contained in the clay at this point. 



is indistinctly marked and is not sudden, but is, usually, grad- 

 ual. Topographically, the exact limit between the two is equally 

 difficult to define, since the elevation of the plateau near the 

 border of the Appalachian mountain province is not sharply 

 contrasted with that of the southeast margin of the latter prov- 

 ince, but the slope of the one gradually passes into that of the 

 other. 



' Annual Report Geol. Survey of Arkansas, 1890, Vol. i, p. 539 et seq. 



