Plate 30 



1. San Cristobal. The fine area shown in the center of plate 29, figure 4, etched very 

 lightly. The kamacite lamellae are gray. Picral 20 seconds; X 150. American Museum 

 of. Natural History. 



2. San Cristobal. The identical area shown in figure 1. With stronger etching the 

 lights and shades are reversed; the kamacite lamellae are now clear (probably because of a 

 film of cold-worked metal caused by polishing, which was removed by the longer etching), 

 while the slightly supersaturated taenite lamellae are darkened. Picral 50 seconds; X 150. 



3. San Cristobal. A local variation in the pearlitic pattern. With light etching the 

 kamacite is gray. Vestiges of octahedral orientation. Picral 20 seconds; X 150. 



4. San Cristobal. Another local variation in pearlitic pattern; coarse irregular lamellae, 

 with orientation, adjoining an area of regular structure. 



150 



