Plate 34 



1. OcTiBBEHA County, Mississippi; nickel-rich ataxite; Ni-Co 62.73 percent. This 

 meteorite, unique because of its extraordinary nickel content, was found in an Indian mound, 

 the mass weighing only 155 grams, of which half was lost. Its authenticity has been doubted 

 by Cohen and others, and it was not included by Farrington among North American meteor- 

 ites. The presence of rhabdites, shown in this photograph, seems definitely to establish its 

 character. Unetched; X 60. American Museum of Natural History. 



2. OcTiBBEHA County. The short needles are not inclusions but etching pits, apparentl}" 

 forming along gamma twinning planes. The nature of the irregular inclusions is obscure. 

 Although they resemble phosphorus-enriched areas they do not darken with neutral sodium 

 picrate etching, and several etchants for carbides were tried without results. They are 

 apparently metallic, owing perhaps to undetermined impurities. Nitric-acetic acid 180 

 seconds; X 60. Harvard University. 



3. OcTiBBEHA County. The grains show characteristic gamma twinning. Nitric-acetic 

 acid 300 seconds; X 600. 



4. Octibbeha County. The intergranular invasion of hydroxide reveals clearly a grain 

 structure, which was not brought out by etching. Nitric-acetic acid 60 seconds; X 60. 



154 



