FURTHER NOTES ON THE PLAINVIEW, TEXAS, 

 METEORITE. 



By George P. Merrill. 

 Head Curator, Department of Oeology, United States National Museum. 



In my paper descriptive of this find/ I called attention to an 

 apparent brecciated structure, the certainty of which could be 

 determined, if at all, only when one of the larger masses could be 

 cut in halves and give opportunity for study of unweathered por- 

 tions. Since that writing, through the liberality of Mr. C. S. Bement, 

 of Philadelphia, the Museum has come into possession of two more 

 of these stones. (Nos. 2 and 3 of pi. 35 of my paper.) This generous 

 gift has enabled me to sacrifice one of the larger individuals already 

 in our possession. No. 4 of the same plate, to the extent of slicing it 

 through the center in a plane parallel to the face there shown. The 

 results of the studies on this and further thin sections are in every 

 way corroborative of the first, which are reviewed below, and the 

 new data likewise presented. 



As descriptive of the appearance of a cut and polished surface, I 

 can not do better than quote the following from the addendum of 

 the first paper : 



When the possibility of breceiation was realized, the smallest (870-gram) 

 fragment of the first find was cut in halves and polished. The resultant sur- 

 faces showed a ground of about equal parts light gray, mainly oxidized to 

 reddish, and darker gray more or less angular areas. Both portions are equally 

 injected with small, but abundant points of metallic iron and iron sulphide. 

 There are also occasional light-gray fragments, some 2 to 4 mm, in length, 

 which are evidently pyroxenic. To the unaided eye both portions are chon- 

 dritic, though this structure is much more pronounced in the dark areas. It 

 was at first thought that this difference might be merely apparent and due to 

 the obscuring of the structure in the lighter portions through oxidation. 

 Further Investigation has, however, shown that this conclusion will not hold. 

 Under the microscope the lighter portion is chondritic and consists wholly of 

 olivine and enstatite with the metallic iron and iron sulphide. None of the 

 twin pyroxenes so characteristic of the dark portion, which was the material 

 described in the first part of this paper, are present. Further than that, the 



» Proc. U. S. Nat. Mus., vol. 52, 1917, pp. 419^22. 



Proceedings U. S. National Museum, Vol. 54— No. 2243. 



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