Plate 45 



1. Leeds, Quebec; medium octahedrite; no anahsis. The specimen, locality unknown, 

 came with other minerals from Leeds and was recognized in 1937. Plessite field showing 

 an imperfect pearlitic pattern. Picral 60 seconds; X 60. 



2. YouNDEGiN, Australia; coarse octahedrite; Ni-Co 7.01 percent. A narrow plessite 

 band with a well-developed pearlitic structure. The taenite border is slightly supersatu- 

 rated. Picral 3 to 5 seconds; X 300. 



3. Seel.\sgen, Prussia; coarsest octahedrite; Xi-Co 5.84(.') percent; as to composition, 

 see plate 38. A plessite field showing pearlitic structure in figure 2. Picral 60 seconds; 

 X 60. 



4. Seel.asgen. Part of the area shown in figure 3. At lower left, kamacite needles 

 with borders of taenite which merge with the taenite lamellae of the pearlitic structure. 

 Compare the similar structure in San Cristobal (pis. 29, 30). As in the latter iron, with 

 strong etching the kamacite lamellae here shown are clear while the taenite lamellae become 

 gray because of slight supersaturation with respect to kamacite. Picral 20 seconds; X 300. 



165 



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