NO. 1881 STONY METEORITE FROM GEORGIA — MERRILL 475 



County (Bluff), Texas stone, as described by the writer,^ but differ 

 in that the latter show no proportional increase in metallic constitu- 

 ents. They seem more nearly comparable with those of the Mocs 

 stone as figured and described by Tschermak.- 



Concerning the origin of the vein-filling matter of meteorites in 

 general, the writer agrees with Tschermak^ and Farrington,* in that 

 it cannot have been derived from inward flowing fused material from 

 the surface, nor can it be due to a fusion of pre-existing particles 

 scattered throughout the mass of the stone. Even were there reason 

 for supposing that the interior of any stony meteorite becomes highly 

 heated during its passage through the atmosphere, the presence of 

 the sulphide filling is indisputable evidence that such did not in this 

 instance occur ; otherwise the sulphide would itself have been con- 

 sumed. The metallic portion cannot be accounted for on the suppo- 

 sition that pre-existing particles were drawn out into filaments 

 through the dragging action of the walls, since it is plain that there 

 has been no such dift'erential movement, nor are there elsewhere in 

 the section any corresponding filamentous forms. The suggestion 

 of Farrington regarding the filling matter of the veins in the Farm- 

 ington, Kansas, stone seems therefore inapplicable here, and one is 

 apparently forced to the conclusion that the sulphide filling at least 

 (ignoring for the time the doubtful metallic constituent) owes its 

 origin to some reducing constituent acting at fairly low temperature 

 at a period since the fracturing took place. 



In respect to structure and texture, the stone is also comparable 

 with that of Mocs, but dift'ers in that the chondrules are compressed 

 and firmly imbedded and break with the groundmass. In the thin 

 section under the microscope the chondritic structure becomes very 

 obscure, indeed, almost unrecognizable, so constant and gradual is 

 the transition into the ground of granular silicates (pi. lviii). 

 Porphyritic and polysomatic forms are not abundant, the prevailing 

 types being radiating columnar or finely granular. Of the two chief 

 constituents, enstatite prevails over olivine in both chondritic and 

 granular forms. Occasional chondrules are composed wholly of 

 small, fairly well developed but closely compacted monoclinic forms, 

 with small angle of extinction, and evidently referable to Dr. W. 



'Am. Jour. Sci., vol. 36, 1888, p. 113. 



* Sitz. d. k. Akad. d. Wiss. Math. Naturw. Classe, vol. 85, 1882, p. 195. 

 *Beitr. zur Classification der Meteoriten, Sitz. k. Akad. der Wiss., vol. 88. 



1883, P, 15- 



* On the Nature of the Metallic Veins in the Farmington Meteorite. .'\m. 

 Jour. Sci., XI, 1901, p. 60. 



