Plate 72 



1. Wood's Mountain, North Carolina; finest octahedrite; Ni-Co 8.61 percent. Normal 

 structure of the iron; the kamacite granulated both in the bands and in the light plessite 

 field (lower right), grains showing Neumann lines. Picral; X 60. 



2. Wood's Mountain. An area similar to figure 1 but in the zone of alteration. A fine 

 irregular granulation has replaced the original larger grain structure. Picral; X 60. 



3. Wood's Mountain. A dark plessite field, similar to that in the upper left corner of 

 figure 1, in the zone of alteration. The taenite particles are partly diffused. The kamacite 

 (left) shows secondary granulation. Very light picral; X 300. 



4. Grant, New Mexico; medium octrahedrite; Ni-Co 9.98 percent. An area at the 

 inner boundary of the zone of alteration. .At the left and below the kamacite is granulated 

 by reheating; above and right, unaltered, with Neumann lines. Two short thick lamellae 

 of taenite with untransformed cores ("spotted" taenite) which with strong etching appear 

 black. Picral 50 seconds; X 30. 



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