METEORITES OF NORTH AMERICA. 217 



In shape they are irregular; each of them presents clear evidence of being fragmentary, the surface being partly 

 smooth and pitted and partly jagged, the latter showing in a remarkably distinct way edges, faces, and crevices which 

 belong to an octahedral structure. Specific gravity, 7.869. 



The polished surface is immediately active in the presence of a solution of copper sulphate. The iron is extremely 

 soft and is easily cut into slices with the saw. On the polished faces of these slices no stony minerals are visible, but 

 there are seen sections of a few rounded cavities, of which the contents have a grayish-black color and a metallic luster. 

 This material is principally composed of finely divided iron which has perhaps been worked into the cavities during 

 the sawing of the specimen and the subsequent leveling of the surface. The rest is graphitic carbon, which may 

 have been sufficient to fill the cavities when the specimen was intact. No chromite was found in the cavities. 



During the polishing of one of the sections a part of its surface was bent inwards and an empty cavity with plane 

 faces was discovered. The quadrilateral bit (?) of the cavity is 6 by 3 mm.; three of the edges of the section of the 

 cavity were seen to be parallel to structure lines visible on the polished surface even before etching; the sides of this 

 cavity were rusty. Similar cavities are found in the iron of Rancho de la Pila, Durango, Mexico. 



The polished and etched surface yields very distinct Widmannstatten figures. On a section not very much in- 

 clined to an octahedral face the beams of kamacite vary from 0.8 to 1.2 mm. in width. They have straight edges, are 

 arranged in groups, and are sometimes continuous for a length of 17 mm. They are separated by very thin layers of 

 tsenite. Plessite is plentiful, but is very homogeneous in structure and not very different in appearance from the 

 kamacite. There is no oriented sheen, such as is presented by the etched surfaces of many meteoric irons. The 

 etching figures and the composition of this iron resemble those of Staunton, Virginia. 



Chromite in the form of a fine powder, small fragments, a thin elongated plate, and a single crystal of very fragile 

 character were found in the insoluble residue of the analysis: 



Fe Ni Co Cu P S Residue 



91.59 7.11 0.60 trace 0.08 trace 0.12 =99.50 



The above percentage composition is approximately that of the Trenton, Rio Juncal, Seneca River, and Staunton 

 irons. 



As stated by Fletcher, the known pieces of this iron are chiefly in the British Museum 

 (2,236 gr.). 



BIBLIOGRAPHY. 



1. 1885: Brezina. Wiener Sammlung, p. 257. 



2. 1887: Fletcher. On a meteoric iron (containing crystallized chromite) found about the year 1880 in Greenbrier 



County, West Virginia., U. S. A. Mineral. Mag., vol. 7, pp. 183-186. 



3. 1895: Brezina. Wiener Sammlung, p. 286. 



Guernsey County. See New Concord. 



GUILFORD COUNTY. 



North Carolina. 



Latitude 36° 4' N., longitude 79° 48' W. (approximate). 



Iron. Medium octahedrite (Om), of Brezina. 



Described 1S22. 



Known weight 200 gr. (7 ounces). 



This mass was first described by Shepard 2 as having been obtained from Professor Olm- 

 sted, of North Carolina. It was one of two pieces of iron, the larger of which was briefly 

 described in the catalogue of Olmsted's collection. 1 The locality of the smaller piece Professor 

 Olmsted stated to be "Guildford" County, 10 or 15 miles distant from the locality of the larger 

 specimen which was found in Randolph County. The individual from whom Professor Olmsted 

 obtained it told him that it had been detached from a large mass weighing 28 pounds, some of 

 which had been worked by a blacksmith into horseshoe nails. The piece preserved is described 

 by Shepard as weighing 7 ounces and as being a distinct crystal in the form of an octahedron. 

 The axis of the crystal, he says, measures 3 inches, and the structure is distinctly foliated, the 

 laminse being pretty uniformly one-twentieth of an inch in thickness. 



Later, Shepard 3 made an analysis of the iron — specific gravity, 7.67 (Rumler) — with 

 results as follows: 



Fe Ni FeS 



92.750 3.145 0.750 =96.645 



