32 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



Six hexahedrites were seen to fall in the last 115 years. Relating 

 this figure to an assumption that perhaps the known meteorites are 

 those which fell in the past 10,000 years, by extrapolation, between 

 500 and 550 hexahedrites should have accumulated in this period. If 

 this assumption is valid, less than 20 percent of all the hexahedrites 

 have been found. 



Although the area of the surface of the earth is slightly less than 

 200,000,000 square miles, only about 57,510,000 square miles of this 

 is land. No consideration has been given to the hexahedrites which 

 possibly fell into the water nor to the fact that only a small percentage 

 of the land surface is effectively observed for meteorite showers. The 

 above figures were obtained, assuming just 6 hexahedrites fell in the 

 last 115 years, and surely there were more. 



If 550 hexahedrites have fallen, and if these were equally scattered 

 over the land surface, there would be one to about every 100,000 

 square miles of land surface. When the area of the places shown in 

 table 8 is compared with this figure (100,000), or if the areas of the 

 localities where hexahedrites seem to be concentrated are compared 

 to this figure, the conclusion is that these particular meteorites are far 

 from being in random distribution. 



INTERFERENCE OF PHOSPHORUS WITH METEORITE 

 STRUCTURES 



Iron meteorites that contain considerable amounts of phosphorus 

 often have strange structures. When the schreibersite develops a 

 skeleton structure, such as that shown in the Lake Murray and other 

 similar meteorites, the kamacite grains enclosing the phosphide body 

 become large and equidimensional. Such kamacite grains interfere 

 with the normal development of the structure in the meteorite. Four 

 meteorites with large phosphide inclusions are shown in plates 1-4. 

 Tombigbee River and Bellsbank are hexahedrites, and Santa Luzia, 

 Sao Juliao de Moreira, and Lake Murray are coarse octahedrites. 



Apparently no chemical analysis is available for the Lake Murray 

 iron, and erratic nickel values will be obtained if the samples selected 

 for study come from certain parts of the iron. In an area adjacent 

 to the large schreibersite bodies, the nickel will be lower than in the 

 kamacite some distance from these phosphide bodies. 



The nickel values in the kamacite around the schreibersite in the 

 Tombigbee River iron are lower than the kamacite more remote from 

 the phosphide bodies (Henderson and Perry, 1958). Similar results 



