Plate 24 



1. HoBA, South Africa; nickel-rich ataxite; Xi-Co 17.00 percent. General structure, 

 with a kamacite needle. Picral 45 seconds; X 100. American Museum of Natural History. 



2. HoBA. Part of a kamacite needle similar to that in figure 1, with portions of the para- 

 eutectoid groundmass. The structure quite exactly resembles that of Tlacotepec and Cape 

 of Good Hope, but the merger of the taenite in the border with the groundmass is more 

 evident. Picral 25 seconds; X 600. 



3. LiNviLLE, North Carolina; nickel-rich ataxite; NI-Co 17.08 percent. General struc- 

 ture, a very uniform and well-developed paraeutectoid structure of rounded kamacite par- 

 ticles in a taenite groundmass. With fairly strong etching the taenite is gray because of 

 slight supersaturation. Man}' kamacite bodies contain droplike inclusions of an iron- 

 phosphide eutectic; such inclusions show no structure with picrate etching but blacken 

 completely. Exceptionally there are small spots where the kamacite bodies are larger and 

 elongated, with some orientation. Picral 50 seconds; X 30. U. S. National Museum. 



4. LiNviLLE. The same structure as figure 3 at higher magnification. Picral 35 seconds; 

 X 150. 



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