METEORITES OF NORTH AMERICA. 149 



Kunz 3 gave the following account of the meteorite : 



Through the kindness of Mr. Moritz Fischer, of the Kentucky Geological Survey, I am now the possessor of a piece, 

 weighing over 2,000 grams, of the meteorite which Colonel Sublet and Mr. Lenoir found on the farm of Elihu Humber, at 

 Powder Mill Creek, about 8 miles west of Rockwood Furnace on the eastern elope of Crab Orchard Mountain, latitude . 

 35° 50' N., longitude 84° 45' W., in Cumberland County, Tennessee (Rockwood being in Roane County). 



It resembles very closely the Hainholz, Westphalia, 1856, and the Newton County, Arkansas, irons, now the Taney 

 County, Missouri. It is scarcely distinguishable from the latter except that in the latter the grains are larger and more 

 readily defined. The specific gravity was found to be 4.745. Chloride of iron (lawrencite) is present in considerable 

 quantities and on a number of sections which had been cut and polished it was perceptible within a short time. It 

 collected in small beads on the piece itself which will undoubtedly lead to a rapid disintegration unless the iron is 

 coated with varnish or some other preservative. Even small fragments have already become seamed, suggesting that 

 the fall is recent. 



Microscopic sections were prepared and in the groundmass of metallic iron were seen clear crystals of anorlhite 

 and olivine. The former are transparent, with inclusions of glass having fixed gas bubbles and of many needle-shaped 

 microlites and some of larger size. The former microlites are probably enstatite, while some black quadratic sections 

 may be chromite or magnetite. The twinning bands of the anorthite are sharp and distinct. The olivine crystals have 

 greenish, brownish veins of alteration (perhaps induced by the lawrencite) with inclusions of glass, microlites, and an 

 abundance of black grains of picotite. These grains are occasionally arranged symmetrically around the crystals as a 

 border, outside of winch is usually a grayish, partly opaque mass between the crystal and the metallic iron. This 

 grayish mass is an alteration of the olivine which in many cases has taken place in the entire crystal and in others leav- 

 ing only a small center of clear olivine. To Mr. J. H. Caswell the writer is indebted for the above microscopical data.. 



In a footnote to this article Kunz states that this meteorite is identical with the Rockwood 

 meteorite and that he gives the name Powder Mill Creek to it because it fell in Cumberland 

 County, Roane County in which Rockwood is situated being adjacent to this. 



Newton 4 states that the nickel-iron in this mass consists of isolated particles arranged in 

 most instances in a system of lines which resembles that of the Widmannstatten figures, as may 

 be seen by holding a polished section in a strong light at some distance from the observer. 

 Cohen 5 found a substance resembling tridymite (asmanite) which, however, he could not inves- 

 tigate more fully at the time. According to Cohen also, Daubree found an abundant exudation 

 of iron chloride in the meteorite. Cohen also remarks that the meteorite appears to be free from 

 olivine and is thereby distinguished from grahamite. 



Brezina 7 makes the following observations: 



The iron here plays the part of a "filler" between the silicate masses. Dark, angular silicate fragments as much as 

 4 cm. in size, lie embedded in a matrix of bright gray, crystalline silicate particles and intermingled, mostly fine, iron 

 particles, so that dark and bright gray fragments are apparently of the same sort; sometimes the same fragments are 

 half bright, half dark. The larger silicate fragments are sometimes intermixed with iron specks and also longer iron 

 streaks. Altered, red-brown olivine crystals attain the size of hazelnuts. 



The meteorite is distributed among collections, about one-third being in the collection of 

 the Field Museum. The latter collection possesses one complete individual weighing 4,315 

 grams which is not mentioned in the published accounts. 



BIBLIOGRAPHY. 



1. 1887: Howell. Rockwood Meteorite. Science, vol. 10*, p. 107. 



2. 1887: Whitfield. The Rockwood Meteorite. Amer. Journ. Sci., 3d ser., vol. 34, p. 3S7-390. 



3. 1887: Kunz. On some American Meteorites. — 5. On the Powder Mill Creek Meteorite. Amer. Journ. Sci., 3d ser., 



vol. 34, pp. 476-477. (Cut of polished slice, and a thin section.) 



4. 1893: Newton. Lines of structure in the Winnebago County meteorites and in other meteorites. Amer. Journ. 



Sci., 3d ser., vol. 45, pp. 152-153 and 355. 



5. 1894: Cohen. Meteoritenlcunde, pp. 220, 232, and 287. 



6. 1895: Meuniek. Revision des lithosiderites, pp. 33 and 37. 



7. 1895: Brezina. Wiener Sammlung, pp. 262-263. 



Cranberry Plains. See Poplarhill. 

 Crawford County. See Mincy. 



