1890.] NEW YORK ACADEMY OF SCIENCES. 191 



Darh Outer Zone of Olivine. 



Per cent. 



SiO, 34.14 



FeO 23.20 



NiO tr. 



CoO 03 



MnO c 09 



MgO 40.19 



S 5.42 



103.07 

 Less for S, 2.71 



100.36 



The specific gravity of the iron freed from olivine was found 

 to be 7.93 at 23.4^ Celsius ; of the olivine, 3.376 at 23.2°. 



The iron is brilliant white, enclosing the troilite and sur- 

 rounding the olivine crystals. Occasionally small etched sur- 

 faces show delicate figures like that of the Linnville Mountain 

 meteorite. 



Troilite exists plentifully, in rounded grains from one to five 

 millimetres in diameter, and in thin folia mixed with and sur- 

 rounding the olivine crystals, as well as running into and filling 

 small spaces in the body of the iron, either as flat plates or 

 rounded masses. Several flat circular plates [crystals ?] of gra- 

 phite, two millimetres in diameter, were observed. 



The olivine crystals are very brilliant, and break out entire, 

 the faces on many of them being distinct enough to measure the 

 angles. The spaces from whicli they break are highly polished, 

 showing every crystal face with a mirror-like lustre ; and in the 

 centre there is a coating of a shining mineral that is jet-black in 

 color, and crushes into a jet-black powder. 



Many of the olivine crystals are in two distinct zones, — the 

 inner half a bright transparent yellow, the outer a dark-brown 

 iron-olivine. In reality this dark zone is an intimate mixture 

 of troilite and olivine, as the analysis by Mr. Eakins and a mi- 

 croscopical examination of the crystals by Mr. J. S. Diller, of 

 the United States Geological Survey, fully prove. 



This group of meteorites, which has recently come to me for 

 description, possesses more than ordinary interest, on account 

 both of the peculiar composition and structure and also of the 

 undoubted ethnological relation, especially because of its prob- 

 able connection with the meteoric iron found in the Turner 

 mounds. (Figs. 4 and 5.) 



In the spring of 1883, Prof. F. W. Putnam found on the 



