TJie Meteoric Iron from Bethany, Great Namaqualand. 27 



resemble the etched surface of a hexahedral iron. With a lens one 

 may see indications of these lines on Fig. 1, Plate VIII. Further, 

 the nickel-iron after etching has a spotted appearance, which can be 

 distinctly seen in the enlarged reproduction. Fig. 2, Plate IX. The 

 spots have indistinct boundaries, and do not, in my opinion, indicate 

 a granular structure, which is likewise contradicted by the con- 

 tinuous etching-lines. 



The main mass of the nickel-iron is undoubtedly kamacite, each 

 broad strip of which may be regarded as forming a simple individual 

 intimately intergrown with taenite. The mode of intergrowth may 

 be best compared with the micro-pegmatitic structure of terrestrial 

 rocks, in which case one may also regard the taenite as forming a 

 simple net-like individual. This cannot be conclusively proved, but 

 it appears to me to be not unlikely. 



In my opinion the broad strips cannot be compared with the bars 

 in octahedral irons with very wide lamellae, as these never show 

 an intergrowth of kamiacite and taenite, but always single kamacite 

 individuals surrounded by taenite. On the other hand, this doubtful 

 portion of the iron resembles in its structure the third variety of 

 plessite, described above as being apparently built up of rods. I 

 conclude, therefore, that the broad strips are best regarded as con- 

 sisting of plessite, which as a rule is composed of intimately inter- 

 grown kamacite and taenite. We may therefore regard this iron as 

 being in certain ways analogous to that from Butler, Bates Co. 

 Both irons agree in having an unusually large proportion of plessite, 

 but they differ in structure and in arrangement of their lamellae. In 

 the, Butler iron these are fairly evenly distributed, but in that from 

 Bethany they are sometimes normally distributed, and sometimes 

 entirely wanting over considerable areas. In spite of such analogy, 

 however, the Bethany iron has a structure peculiar to itself, and 

 Professor Berwerth informs me that even in the almost exhaustive 

 collection of the Vienna Museum there is not one iron that can 

 be directly compared with it. 



The slices examined show few accessory constituents, and those 

 found are of small size. I have observed only fifteen troilite inclu- 

 sions, all of elongated shape, and with boundaries which are rather 

 irregular, and occasionally finely zigzag. Their length varies from 

 4 to 8 mm., and their breadth from 1 to 1-5 mm. 



Usually they are surrounded by a zone of kamacite, but in some 

 instances the lamellae are directly in contact with the troilite, a 

 condition which is rather rare. 



The dark spots on the right in Fig. 2, Plate VIII., are troilite. 



