CHICORA METEORITE — PRESTON, HENDERSON, RANDOLPH 411 



olivine is made up of alternating zones of olivine and a granular, fine- 

 grained, crystalline aggregate. The olivine bands in a given chondrule 

 fragment will extinguish under cross Nicols as a crystallographical 

 unit. The origin of this banded structure of the olivine must have 

 taken place when the original chondrules were formed. These were 

 broken up and their fragments added to this mineral aggregate. 



(b) There are a number of subhedral olivines present, and their 

 outer areas have been badly granulated, while the central portion, 

 although fractured, is not nearly so badly broken up or shattered. 

 It appears that this shattering of the outer zones of the olivine has 

 taken place after the consolidation of this mineral aggregate. 



Oligoclase was found in the insoluble residue, and as several tests 

 were made for aluminum in the acid-soluble portion and none found, 

 it seems certain that no anorthite is present. Tlie grams are small 

 and free from twinning, and no evidence of any internal strains could 

 be detected. The quantity present was obtained by recalculating the 

 analysis of the insoluble residue, assuming that all the aluminum 

 belonged to the oligoclase molecule. Oligoclase was found to make 

 up 7.20 percent of the total meteorite. 



Table 5. — Compositions of the pyroxenes in the Chicora meteorite, obtained by 

 correcting the mialysis of the insoluhle material for ogligoclo.se 



1 Thus if all the AI2O3 found in the insoluble portion is assumed as belonging to oligoclase, the analysis 

 of the insoluble portion can be corrected for the obligoclase present. 



Table 6. — Optical properties of hypersthene in the Chicora meteorite 

 J. J. Glass, Observer 



