38 BULLETIN 149, UNITED STATES NATIONAL MUSEUM 



Daher die vollstandigen Ubergange in Siderite und die Deutlichen Korrosion- 

 serscheinungen an den grossen Olivinkristallen der Pallasite. 



C. Klein, in 1906 ^^ evidently basing an opinion largely on figures 

 of chondrules in the works of Hahn and Tschermak, affirmed that 

 there occur many ideally perfect forms that lack the eccentric radiat- 

 ing structure, but are "radial strahlig" from a center, equally in all 

 directions and are true spherulites. Those not having this perfection 

 of structure are considered fragments. It may be well to note before 

 going further, that Klein apparently stands alone in holding these 

 views though they may be correct for certain forms. 



Wahl ®^ would explain the formation of the chondrule as due to 

 the cooling of a silicate melt in a heated atmosphere, the resultant 

 drop crystallizing from the surface inward. 



Die Entstehung der Chondren lasst sich also ganz allemein als durch Zer- 

 staubung von Silikatschmelz fluss innerhalb einer heissen Atmosphare und 

 Kristallization der hierdurch enstandenen Tropfen von aussen nach innen zu 

 erklaren. 



This again would seem to refer only to the cryptocrystalline, 

 radiating enstatite, and the barred and monosomatic olivine chon- 

 drules. 



Finally in 1913, Fermor ^^ of the India Survey, suggested that the 

 chondrules are remelted garnets. 



The views of the present ^vriter have been set forth elsewhere ^^ and 

 need not be repeated here in their entirety. It suffices to say that 

 struck by the discordant character of the views expressed he studied 

 the forms not merely as shown in the thin sections, but in their 

 complete forms as freed from the matrix of some of the more friable 

 stones. (See pi. 25.) It was found (1) that the most perfectly spherical 

 and oval forms occurred in those stones the tufl'aceous nature of 

 which was beyond question. These show a cryptocrystalline or 

 radiating internal structure and are mineralogically of pyroxene. (Fig. 

 5, pi. 22, and fig. 1, pi. 25.) They often show excrescences or saucer- 

 shaped 'depressions, as through shrinkage or interference during 

 solidification. (2) Other forms, more irregular in shape (fig. 2 of 

 plate 25) show a rougher surface, and interiorly are of a polysomatic 

 nature — composed of phenocrysts of olivine or pyroxene in a more 

 or less glassy base or of an almost holocrystalline aggregate of one or 

 more minerals. His conclusions were then to the eft'ect that: 



1. Only the chondrules of glass and cryptocrystalline or radiating 

 enstatites (kugelchen) present the rounded or oval form with smooth 

 rindlike crust and surfaces, with often one or more saucerlike depres- 

 sions or excrescences such as are consistent with a theory of origin 

 as fused drops of "fiery rain." (Sorby.) 



S3 Studien uber Mcteoriten, p. 35. 

 SI Zeitschrift Anorg. Chem., vol. 69, 1910, pp. 52-96. 

 «' Records Qeol. Survey India, vol. 43, 1913, p. 45. 

 89 Proc. Nat. Acad. Sci., vol. 6, 1920, p. 449. 



