PALLASITE.— CUMBEELANDITE. 81 



containing actinolite, serpentine, etc. ; and the question of the formation of 

 certain schistose rocks by nietamorjjhisin of these terrestrial pallasites is an 

 interestino- one. 



A similar structure to that of this Rhode Island pallasite has been 

 reported in some New York and Canada iron-bearing rocks. 



Taherg, Sweden. 



Of a similar character to the Cumberland pallasite is the rock from Taberg, Sweden, 

 so long known and so well described by Messrs. Sjoren and Tornebohm.* 



The section in the collection purchased from Kichard Fuess of Berlin shows an 

 imperfect sponge-like mass of magnetite, holding olivine and feldspar. 



The olivine is niucli fissured and traversed along the fissures by serpentine and mag- 

 netite bands, wliile in places it is entirely replaced by the secondary serpentine. 



The feldspar is in irregular, somewhat kaolinized masses, holding olivine and mag- 

 netite grains. The feldspar polarizes with a polysynthetic structure. 



A reddish-brown secondary biotite is associated with the magnetite, but is more 

 abundant than it is m the Cumljerland rock. 



For the full description of this rock the reader is referred to the original papers 

 above mentioned. This rock is figured on Plate II. figures 2 and 3. Figure 2 shows the 

 sponge-like magnetite with the inclosed olivine, while figure 3 shows a more highly 

 altered portion of the same section in which the magnetite has jjartly disappeared and 

 the silicates contain more ferruginous material. The reddish-brown portions are the 

 secondary mica, usually associated with or replacing the magnetite. 



The pallasites may then be described in general terms as composed of a 

 ferruginous sponge-like or semi-sponge-like mass, holding olivine with or 

 without feldspar, enstatite, diallage, augite, and chromite, or spinel min- 

 erals. The sponge is formed either by native iron with pyrrhotite, or by 

 their secondary products, like magnetite. 



The alteration of these original materials gives rise to serpentine, clno- 

 mite (?), biotite, actinolite, etc. 



The' general structure of the Cumberlandite from Rhode Island mav be 

 summed up as follows : In the least altered condition it shows a dark resi- 

 nous, crystalline, splintery and compact mass, holding porpliyritically inclosed 

 feldspars, which, althovtgh characteristic of one portion of the locality, are 

 not essential. This rock passes into a form destitute of feldspar, but having 

 the same groundmass, which contains patches of a dark-green, fine-grained 

 alteration-product, which holds a similar relation to the groundmass as the 

 feldspar in the preceding. In the succeeding forms the resinous groundmass 



* Geol. Foren. Forhau., 1870. iii. i2-62 ; ISSl, v. 610-619; 1SS2, vi. 261-267; Neues Jalir. Miu., 

 1S76, pp. 434, 435 ; 1SS2, ii. 66, 67. 



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