PALLASITE. — CUMBERLANDITE. 75 



lowish metallic particles are to be seen. The microscopic and chemical examination 

 showed that the rock was composed of nickeliferous iron, pyrrhotite, chromite, olivine, 

 and bronzite. The nickeliferous iron forms the cementing mass, in a fine irregular net- 

 work. In the finer meshes lie single crystals, and m coarser portions are inclosed aggre- 

 gated grains and crystals of the above mentioned minerals. This iron is of a very light 

 steel gray color, and, on etching its surface, shows under the microscope figures somewhat 

 similar to those of the Senegal iron. 



The olivine forms more or less perfect crystals, whicli occur botli in the iron and as 

 intergrowths witli the bronzite. The olivine was determined by the crystallographic 

 measurements of Professor Viktor von Lang to be of tlie same form as basaltic olivine. 

 It is on the surface of a bluish-gray to a berlin-blue color, but in tlie thin section pale 

 green. 



Under the microscope no well marked cleavages were seen, but undulatmg fissures 

 parallel to the basal piuacoid are common. Many of these cracks are bordered by a moss- 

 like black mineral, which Tschermak regards as chromite, arising fi'om a secondary altera- 

 tion of the olivine. Judging from the figure given, the present writer would agree in 

 tliis particular with Tschermak. 



Tlie bronzite occurs in gi"ains and ii'regular crystals. From its crystallographic char- 

 acters, as determined by Von Lang, it appears to be enstatite, the same as the lironzite 

 in the Breitenbach meteorite. The enstatite has an asparagus-green to a yellowish- 

 green color, and under the microscope is of a very pale green shade. It is traversed by 

 the usual cleavage and fissure lines, and contains inclusions of three different kinds. The 

 first is in the form of colorless rounded grains, which are regarded as feldspar. The next 

 class of inclusions are minute, round, black particles, which are referred to chromite. 

 The last class are fine hair-lilve bodies, like those commonly seen in terrestrial bronzite, 

 but whose nature was not determined by Tschermak. 



The pyrrhotite was seen united with the iron, and often between the silicates in yel- 

 low grains having a metallic lustre. 



The chromite occurs in black crystals and gi'ams, possessing a strong semi-metallic 

 lustre. The planes of an octahedron, rhombic dodecaliedron, and tetragonal triakis octa- 

 hedron were observed by Von Lang upon the chromite crystals. It was found in small 

 amounts between the silicate, and also in the iron. For a fuller tlescription and the 

 figures, the reader is referred to the original paper with its accompanying plate.* It is 

 doubtful whether tliis meteorite should be placed here, or classed with the peridotites. 



Variety. — Cumberlandite. 

 Iron Mine Hill, Cmnherlcmd, Ilhode Island. 



E"o. 998. A dark resmous, almost black, crystalline groundmass, holding, porpliy- 

 ritically inclosed, long, striated, glassy, and milky plagioclase crystals. Powder strongly 

 magnetic. This rock has been exposed on one side to weathering, and shows a dark 

 brown mass holding grains of magnetite, and gives an earthy yellow streak. In some of 

 the unaltered portions, the groundmass has the oil-green color of olivine. Tlie fracture 



* Sitz. Wieu. Akad., 1S70. Ixi. (2), 465-475. 



