METEORITES OF NORTH AMERICA. 183 



iron is to be found in the sections. The groundmass is stained a ferruginous yellow in many places, and the commence- 

 ment of a serpentine alteration was observed in some of the olivines. 



The feldspar is in irregular glassy masses and in imperfect crystals showing striation and extinction oblique to the 

 nicol diagonal. They contain inclusions apparently of olivine, enstatite, magnetite, bubble-bearing glass cavities, etc. 



The olivine and enstatite also contain glass inclusions, magnetite, etc. The enstatite in some places is dichroic 

 along its cleavage planes owing to its slight greenish alteration. 



These sections having been prepared by a student are of such thickness and ground with so uneven a surface 

 that the study of them is very difficult. A few grains resemble quartz but they are probably unstriated glassy feldspar. 



From the various descriptions given it is to be concluded that the Estherville peridotite varies considerably in its 

 mass in different portions — from those parts entirely iron, those of a spongelike iron mass holding silicates, those of but 

 little iron with the silicates, and those that are pure or nearly pure silicates. If detached portions should be taken and 

 analyzed chemically and microscopically it could be claimed that this meteorite is a siderolite, a pallasite, a peridotite, 

 and all be equally correct so far as the portion examined would show; but studying this meteorite as a whole its proper 

 place, both chemically and microscopically, appears to be with the peridotites. The variations in the descriptions 

 given by the different observers who have examined this meteorite are doubtless owing, in many cases, to the actual 

 variation in the rock itself. It offers a striking illustration of the need of some more general method than a purely 

 mineralogical one in the naming of rocks. 



Since the preceding was written specimens of this meteorite containing peckhamite have been received from 

 Professor Peckham. 



These later sections obtained from Professor Peckham (containing peckhamite) present for the mass of the meteorite 

 the same composition and structure as those obtained from Professor Hall. The peckhamite presents the optical 

 characters and cleavage of enstatite but is filled entirely full of vapor cavities, iron, glass, brown grains, etc. To these 

 inclusions is apparently owing the coloid appearance of peckhamite and the variation in its analysis; while Meunier 

 probably mistook plagioclase for this mineral. 



Meunier, 17 in his revision of the lithosiderites in 1895, makes the following further obser- 

 vations : 



Thin slices examined under the microscope show large crystals of peridot, poorly defined, full of cracks, very 

 active in polarized light and containing various inclusions. These crystals, evidently worn upon the surface, rounded 

 and cracked, are buried in a crystalline magma, very thin where it is marked by elongated grains of pyroxene, small 

 crystals of triclinic feldspar, and numerous opaque granules, which by special effort I was able to recognize as oxidized 

 iron, more or less chromiferous. 



Brezina 18 in 1895, also reported further, as follows: 



A lady's finger ring made from the iron of this mesosiderite was procured for the Vienna Museum with the Kunz 

 collection. A nodule, rich in iron, cut in two, showed upon the etched surface grains of iron surrounded by grains of 

 troilite and covered with fine Widmannstatten figures. One of these inclosed a retort-shaped troilite concretion. 

 Another Estherville section showed a fresh brown olivine crystal 1.5 to 2.5 cm. in size with perfect cleavage. 



The meteorite is pretty well distributed among collections. London possesses 117 kgs., 

 Minneapolis the 151-pound mass., Paris 50 kgs., Yale 48 kgs., Harvard 18 kgs., and Vienna 23 

 kgs. Torrey and Barbour 16 state that 500 pounds (presumably including the 437-pound mass) 

 were sent to the British Museum and subsequently divided between London, Paris, and Vienna. 



BIBLIOGRAPHY. 



1. 1879: Peckham. Fall of a meteorite on the 10th of May, in Iowa. Amer. Journ. Sci., 3d ser., vol. 18, pp. 77-78. 



2. 1879: Shepard. On the Estherville, Emmet County, Iowa, meteorite of May 10, 1879. Idem, pp. 186-188. 



3. 1879: Hinrichs and Daubree. Comptes Rendus, Tome 88, pp. 1219-1220. 



4. 1880: Smith. Study of the Emmet County meteorite that fell near Estherville, Emmet County, Iowa, May 10, 



1879. Amer. Journ. Sci.,-3d ser., vol. 19, pp. 459^63 and 495. (Analysis.) 



5. 1880: Smith. A new meteoric mineral (Peckhamite) and some additional facts in connection with the fall of meteor- 



ites in Iowa, May 10, 1879. Amer. Journ. Sci., 3d ser., vol. 20, pp. 136-137. (Analysis.) 



6. 1880: vom Rath. Verhandl. naturhist. Verein Bonn, Bd. 37 (Sitzber.), pp. 239-241. 



7. 1880: Hoffmann. Idem, pp. 285-287. 



8. 1881: Brezina. Bericht III. Sitzber. Wien. Akad., Bd. 84 I, pp. 278 and 279. 



9. 1882: Meunier. Determination lithologique de la meteorite d'Estherville, Emmet County, Iowa (10, May, 1879). 



Comptes Rendus, Tome 94, p. 1659-1661. 



10. 1883: Tschermak. Beitrag. Sitzber. Wien. Akad., Bd. 88 I, p. 351. 



11. 1883-1885: Tschermak. Photographien, pi. 24, pp. 22 and 23. 



12. 1884: Wadsworth. Studies, pp. 92-101. 



13. 1885: Brezina. Wiener Sammlung, pp. 155 and 168. 



14. 1888: Newton. Orbits. Amer. Journ. Sci., 3d ser., vol. 36, p. 4. 



