400 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



The relatively high content of copper and low specific gravity is also remarked by Cohen. 

 The meteorite is distributed. The Yale collection has 985 grams, the British Museum 524 

 grams, and the Harvard collection 304 grams. 



BIBLIOGRAPHY. 



1. 1850: Silliman. Notice of two American meteoric irons. Proc. Amer. Assoc. Adv. Sci., vol. 4, pp. 36-37. 



(Analyses). 



2. 1851: Shepard. Amer. Journ. Sci., 2d ser., vol. 11, p. 40. S. audi Liebig-Kopp, Jahresber., 1850, p. 826. 



3. 1859-1862: Von Reichenbach. No. 9, pp. 162, 175, 176, 182; No. 11, p. 291; No. 15, p. 100; No. 17, pp. 268, 269; 



No. 18, p. 488; No. 21, pp. 578, 588. 



4. 1863: Rose. Meteoriten, pp. 70 and 153. 



5. 1884: Meunier. Meteorites, pp. 99, 131, and 132. 



6. 1885: Brezina. Wiener Sammlung, pp. 203, 219, and 234. 



7. 1893: Meunier. Revision des fers m^teoriques, pp. 15 and 18. 



8. 1900: Cohen. Meteoreisenstudien X. Ann. K. K. Naturhist. Hofmus. Wien., vol. 15, pp. 74-77. 



9. 1905: Cohen. Meteoritenkunde, Heft 3, pp. 275-278. 



SAN ANGELO. 



Tom Green County, Texas. 



Latitude 31° 20' N., longitude 100° 20' W. 



Iron. Medium octahedrite (Om) of Brezina. 



Found, 1897. 



Weight, 88 kgs. (194 lbs.). 



This meteorite was described by Preston ' as follows: 



The San Angelo siderite is oblong in shape and was, previous to cutting, 51 cm. long by 29 cm. wide and 14 cm. 

 thick. Its weight was 194 pounds, or 88 kgs. A considerable portion of this siderite was obtained by Prof. H. A. Ward, 

 chief of Ward's Natural Science establishment, through the courtesy of Prof. Geo. P. Garrison of the University of 

 Texas, Austin, Texas, and he is indebted to Mr. James Abe March of San Angelo, Texas, for the facts in reference to its 

 locality, and the manner in which it was found. 



It was discovered by Mr. John Johnson on the prairie 7 miles south of San Angelo, Tom Green County, Texas, about 

 July 1, 1S97. The prairie on which the meteorite was found is called "Lipan Flats," a body of land entirely devoid of 

 vegetation, without even mesquite trees. The meteorite was partially buried in the soil, and Mr. Johnson discovered 

 it while riding horseback in search of cattle, and states that unless one rode over it, it would not have been seen, as the 

 color of the soil and the meteorite were nearly the same. 



The exterior surface of the mass is of a dark reddish-brown color, considerably spotted with large yellow patches. 

 None of the original crust is perceptible. The surface is very much oxidized and some places can be seen where scales 

 a quarter of an inch or more in thickness have flaked off, thus intimating that the mass had lain for many years in its 

 original position where discovered. The surface of the iron is marked on all sides by large and characteristic pittings, 

 some of them as much as 12 cm. in diameter. 



At one end of the meteorite several ounces had been forced from the main mass, which has left a rough, jagged 

 surface 5 by 6 inches. 



This is of unusual interest, as the octahedral structure of the iron is beautifully shown by numerous octahedral faces, 

 the largest of which is 1.25 inches in diameter and is very sharp and clear. So also are many of the smaller octahedral 

 faces shown over this surface where the separation of the mass was made. 



A portion of this part taken off has been forged in a blacksmith shop ; this piece when polished and etched has the 

 same general appearance as have all forged meteoric irons we have seen. 



On slicing the mass we find the troilite nodules very scarce, the largest and only prominent one we have come across 

 being 26 cm. in its greatest diameter and continuing of this size only through three thin slices. The Widmanstatten 

 figures are brought out sharp and distinct on the etched surfaces, and are much more regular both in form and size, than 

 in any other iron with which I am familiar. The rhombic figures are from 1 to 1.5 inches in diameter, and vary but 

 little throughout the mass. The so-called Laphamite lines are prominently present, extending across the large patches, 

 of plessite. 



There are two exceedingly interesting veins which appear on either end of most of the slices, that are filled with a 

 black, lustrous graphitic-looking mineral; the longest of these veins following the curve is 11 cm. and varies from 1 to 4 

 mm. in width; the other is 6 cm. long with a like variation of from 1 to 4 mm. in width. 



Another distinguishing feature of this iron are the numerous small fissures or cracks, usually extending from the 

 exterior surface inwards, and following in a zigzag course along the edges of the kamacite plates, and in some instances 

 the rhombic form of the Widmanstatten figures as seen on the etched surface, is strongly outlined by these fissures. These 

 show clearly that with a little more heat the expansion of these cracks or fissures would have caused masses to separate 

 from the iron, which would tend to cause the large pittings, as suggested by me in an article in the January number 

 of this year of this journal. In one case, if a separation had taken place along these fissures, it would have created a 



