486 SMITHSONIAN MISCELLANEOUS COLLECTIONS [VOL- 50 



Lawrencite o . 14 



Aragonite 0.80 



Andradite 2 . 45 



Quartz 0.21 



99-77 

 The work of Tassin, next to be referred to, throws doubt upon 

 these conclusions, it being claimed that the magnetic character of the 

 shale is due to the minute particles of unaltered schreibersite, already 

 noted. The origin attributed to this oxide, either in the form of 

 fragments or the oval and pear-shaped masses, by the writer is 

 given below in the consideration of — 



The Shale Balls. — In the publication by Mr. Barringer reference 

 is made to the finding, principally in pits and open trenches on the 

 north side of the crater rim, of numerous nodular masses of more 

 or less oxidized meteoric material, to which the name "shale balls" 

 was given. These were studied by Merrill and Tassin, 1 the con- 

 clusion reached being that such represented chloride-sulphide rich 

 masses of the iron which, through the protective action of the earth, 

 had escaped complete oxidation and afforded an opportunity for the 

 observation of the transition stages (pi. lxxiv). In short, that the 

 iron shale was, as surmised by Derby and others, but a product of 

 natural oxidation, after reaching the ground, of a peculiarly sus- 

 ceptible phase of the iron. Such an origin seemed absolutely proven 

 in cases where a cross-section showed the plates of unoxidized iron 

 phosphide still retaining their original orientation, although the 

 nickel iron had all gone over to the condition of limonite. In 

 many of the smaller blebs no such transition could be observed, and 

 their like origin is assumed from analogy only. It is to be noted 

 that the contention of Messrs. Barringer and Tilghman apparently 

 finds support from Lockyer. 2 



The relationship of the shale-ball irons to the typical irons is ex- 

 pressed as follows : 



We have therefore come to the conception of a large heterogeneous mass 

 of nickel-iron with segregation masses rich in chlorides, phosphides, and sul- 

 phides. Such would naturally rupture most readily along the line of con- 

 tact with the more homogeneous portions, and, moreover, the results of at- 



1 Smith. Misc. Collections (Quarterly Issue), vol. 50, 1907, p. 203. 



' Meteoric Hypothesis, p. 69. He says : "It is natural to suppose that 

 meteors in their passage through the air break into fragments ; that incan- 

 descent particles of their constituents, including nickel-iron, manganese, and 

 the various silicates, are thrown off, and that these, or the products of their 

 combustion, eventually fall to the surface as almost impalpable dust, among 

 which must be magnetic oxides of iron more or less completely fused." 



