394 Foote — New Meteoric Iron from West Australia. 



10 cm across and less than one-half as deep as their lateral radius. 

 On the thick edge of the iron shown in the extreme left corner 

 of fig. 1 is a pit about 2 cm broad and 2 cm deep, due to the 

 aerial burning out or terrestrial oxidation of a surface nodule. 

 The heavy oxidation in the large deep pit indicates that the 

 meteorite did not fall recently. 



After making casts, the mass was sawed at Philadelphia in a 

 direction that would outline the deeper pits in cross section 

 (fig. tt). The iron is exceptionally hard, due in part to the 

 presence of occasional patches and thin leaves of schreibersite. 

 On the etched surface these appear as long needles, one meas- 

 uring T6 mm long and only 1 to 2 mm broad. This mineral also 

 encases some of the nodules of troilite (fig. 5) which are fre- 

 quent and range up to 3'5 cm in length ; some at the surface are 

 exposed on sawing. The largest so far uncovered (fig. 5) 

 includes small rods and nodules of olivine about 2 to 3 mm across. 

 The olivine appears to be opaque brownish-black, but under 

 the microscope shows a yellowish-brown translucency and 

 internal reflections. Another inclusion shows as dark capillary 

 lines about 2 cip long, separating two parallel bands of kamacite. 

 These minute fissure-like plates lie on edge, sometimes in par- 

 allel series and again without regular arrangement. When 

 etched or broken, the iron is light gray. Polishing and etch- 

 ing with dilute nitric acid brings out the structure of a medium 

 octahedrite, the kamacite bands mostly ranging between 0*5 

 and l-5 mm broad. These are strongly outlined by the brighter 

 taenite, the two making up the greater part of the mass. The 

 predominance of kamacite bands and the relative scarcity of 

 plessite groundmass tends to slightly confuse the otherwise 

 very striking Widmanstatten figures. Two full size photo- 

 graphs of the same slab illustrate a common feature of meteoric 

 irons. Fig. 5 shows the soft-toned kamacite and plessite which 

 are prominent in most lights. Fig. 6 shows the same subject 

 held at an oblique angle to catch the fullest reflections of the 

 more brilliant taenite and schreibersite, thus obscuring, in part, 

 the main constituents. The taenite is uniformly distributed 

 throughout the mass. Its variation in fig. 6 is due to the 

 etched surface not being perfectly level. Even the condensa- 

 tion of moisture from breathing on a polished surface momen- 

 tarily develops well-marked figures of kamacite and plessite. 



On comparing the Mount Edith iron with over two hundred 

 meteorites, a close resemblance to the Bella Roca (Mexico) 

 iron was observed. This likeness extends to all of the crystal- 

 line features, except the dark capillary lines before referred to. 

 Bella Poca, however, according to Whitfield, contains 1*53 

 per cent less nickel and 1*98 per cent more iron than Mount 

 Edith. 



