Plate 6 



1. Holland's Store, Georgia; granular hexahedrite; Xi-Co 6.35 percent. This peculiar 

 iron shows two distinct areas of structure. The greater part consists of macroscopic grains 

 with diversely oriented sheen, within which is a finer granulation; the remainder resembles a 

 nickel-poor ataxite, though occasionally enclosing small spots of granulation. The picture 

 shows the abrupt transition from the one to the other. Picral 75 seconds; X .^0. 



2. Holland's Store. Part of the area without granulation. One set of Neumann lines 

 is visible. The lines are generally absent, though in one part of the specimen several large 

 rounded grains, bounded by thick black lamellae, show a profusion of them. The black 

 particles, in part aligned on a hexahedral plane, are apparently oxide, though Brezina 

 mentions the occurrence of grains of magnetite. Picral 40 seconds; X 60. 



3. Walker County, Alabama; hexahedrite; Ni-Co 5.94 percent. An anomalous pearl- 

 itic structure, the only example observed by the author in a hexahedral iron. The gray 

 lamellae are taenite, darkened slightly with rather strong etching by reason of supersatura- 

 tion with respect to kamacite, as in the pearlitic areas in San Cristobal. Compare plates 

 29, 30. The alternate clear lamellae are kamacite. Picral 40 seconds; X 600. 



4. Walker County. The white quadrangle, surrounded by oxide, has the pearlitic 

 structure shown in figure 3. This minute spot was the only place where the structure was 

 found. Picral 40 seconds; X 60. 



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