522 G. P. Merrill — Minor Constituents of Meteorites. 



terrestial rocks, matters to which attention was called in the 

 paper above referred to, but which with the additional data 

 now at hand can be elaborated. The meteorites, as there 

 shown, are in any degree comparable only with the most basic 

 of terrestrial igneous rocks, mainly with the peridotites or 

 pyroxenites, rarely with the basalts. Omitting the silicates 

 common to both groups and limiting consideration to the 

 metallic and minor constituents, we find, first, nickeliferous 

 iron and iron phosphides almost universally present in meteor- 

 its, but rare in terrestrial rocks. Exceptions must be made in 

 favor of the iron in the Greenland basalt, and the more recent 

 discovery of native iron in the basalt of Buhl, Germany,* 

 besides a few minor occurrences in basalts and diabases. 

 Sufficient for now that it does occur, though rarely, as is to be 

 expected from the energetic oxidizing disposition of our atmos- 

 phere. Iron sulphides are common to both groups, though it 

 is apparent that the idea first promulgated by Rose to the 

 effect that the monosulphide troilite is limited to certain classes 

 of meteorites is erroneous. 



Carbon, either as diamond, graphite, or an amorphous condi- 

 tion, or again as CO, C0 3 or as a hydrocarbon of uncertain 

 formula, is now recognized as a common constituent of meteor- 

 ites, f both stony and iron. Except as in form of the diamond, 

 however, this element has, so far as I am aware, never been 

 reported in terrestrial peridotites, though it does occur in the 

 metalliferous portions of the iron-bearing basalt of Greenland. 

 Where occurring in igneous rocks it is with this exception 

 wholly in those of a granitic or syenitic type. 



In Washington's compilation of analyses^: there are reported 

 among the unusual elements of terrestrial peridotites, only ; 

 (1) titanium, (2) phosphorus, (3) manganese, (4) zirconium, 

 (5) strontium, (6) boron, (7) nickel, and (8) vanadium. Whether 

 or not other elements were looked for is not stated, but from 

 what is known of the character of the analysts it is safe to 

 assume that they were. Eakins, in a wehrlite from Red Bluff, 

 Montana, reported§ 0*81 per cent Ti0 2 ; 0*12 per cent P 2 5 ; 

 0*08 per cent MnO ; 0*16 per cent NiO ; and a trace of BaO. 

 Also in a peridotite from Silver Cliff, Colorado, 0'17 per cent 

 P 2 5 and 040 MnO. Hillebrand, in an analysis of a perido- 

 tite from Opin Lake, Marquette region, Michigan, found 0*66 

 per cent Ti0 2 ; 0-17 per cent P 2 5 ; 0*12 per cent MnO ; with 

 traces of BaO and SrO. The same authority found 0'26 per 

 cent Ti0 2 with traces of P 2 5 and Zr0 2 ; 0*22 per cent MnO ; 



*F. F. Hornstein, Centralblatt Min., 1907, p. 276. 



fSee Cohen's Summary, Meteoritenkunde, vol. i, pp. 138-82. 



% Professional Paper, No. 14, U. S. Geological Survey. 



§ Prof. Paper, No. 14, U. S. Geological Survey. 



