Plate 54 



1. Zacatecas, Mexico. Classified as a brecciated octahedrite, although the specimen 

 studied shows no octahedral structure. The most satisfactory analysis, given by Cohen 

 (Cohen and VVeinschenk, A'leteoreisen-Studien, vol. 5, p. 51, 1897) gives Ni' 5.98 percent, 

 Co 0.91 percent, P 1.02 percent. Copious segregations of phosphide along grain boundaries; 

 compare Soper, pi. 11). Picral 75 seconds; X 30. 



2. Zacatecas. In other parts of this iron, as here shown, the phosphide appears as a 

 thick dispersion of minute particles. Picral 50 seconds; X 60. 



3. Wichita County, Texas; coarse octahedrite; Ni 7.93 percent, Co 0.40 percent (Cohen, 

 in Cohen and Weinschenk, 1891). The phosphorus content is not available, though it 

 obviously is considerable. The fine dispersed particles are absent in the vicinity of the 

 schreibersite bodies. Picral 35 seconds; X 60. 



4. CowRA, Australia; ataxite or finest octahedrite; Ni-Co 14.25 percent. The abundant 

 kamacite spindles (pi. 17) contain many inclusions of schreibersite. An example of such 

 an inclusion in an area near the surface of the mass, which shows a characteristic iron- 

 phosphide eutectic structure. Picral 30 seconds; X 150. 



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