METEORITES OF NORTH AMERICA. 81 



meteorite of 19 ounces in weight besides the large one, but the rest were found in groups of small meteorites from about 

 a pound in weight to the size of a pea. Each group was scattered over an area of 15 to 30 square yards. The larger 

 individuals of the groups show themselves true pallasites and even some very small ones, but many of these latter are 

 largely oxidized, the metallic iron having all disappeared. All stages of oxidation are shown in each group. The 

 large mass and three groups — the smallest weighing 3 pounds and numbering 400 individuals — are in possession of 

 the writer, at Junction City, Kans. 



Meunier e gives the following account of a study of the structure of the meteorites : 



The Kiowa meteorites have been studied by several American scientists such as Snow, Huntington, and Kunz, 

 who published the analysis by Eakins and Hay. But their geological history has hitherto been neglected. 



It is to be noted first that different mineralogists are far from being unanimous in their determinations, these 

 divergences being due in part at least to the fact that their specimens were not identical. In order to get an adequate 

 idea of the Kiowa meteorites it is essential to use enough specimens to show the variations of which the fall is sus- 

 ceptible. 



Within limited areas massive blocks of iron, without any admixture of stony matter, have been recognized, while 

 other portions are of a spongy nature with the cavities in the iron filled up with stony matter. In the latter instance 

 the meteorite resembles the celebrated Pallas iron; so that several authors have included the American specimens in 

 the type pallasite of Rose. This conclusion appears to be erroneous. 



The metallic portion presents two principal alloys of iron and nickel, that is, tsenite (Fe 6 Ni) and plessite (Fe I0 Ni). 

 In this respect Kiowa differs from the pallasite variety whose metallic network is composed of tsenite and kamacite; 

 it was on this account that Kunz wrongly called this metal caillite. According to ite composition, it coincides with a 

 wholly metallic type of meteorite which since 1870 I have designated as jewellite. 



Nevertheless the structure of the metallic part is not that of jewellite, the difference being due to special lithogenic 

 conditions. Apart from the peridotic particles, the mass is formed of laminae of tsenite arranged in bundles which 

 intersect under the angles of the octahedron. The spaces between the laminse are filled with plessite, which is dis- 

 tinguished at first sight by its color, which is a very dark gray, contrasting with the appearance of polished steel in the 

 case of the other alloy. Frequently the plessite forms little isolated specks of a fusiform outline or more or less circular or 

 entirely irregular, bordered by more or less extended laminae of tsenite, a condition not noticed in any other meteoric iron. 



In proximity to the grains of peridote, the relation of the two alloys frequently takes on another character and, 

 although the Kiowa meteorite does not present in the same degree the concretionary and concentric character of the 

 pallasite, one frequently notes an evident enveloping of the silicate grains with nickel-iron. It is then the plessite 

 which is in contact with the stony mineral; it constitutes a zone frequently very thick and whose exterior outline is 

 not then in the least parallel to the profile of the peridote. In more than one place several grains of olivine are enveloped 

 in the same mass of plessite, which may at the same time contain different nodules. These latter are usually of 

 pyrrhotine, in small amounts, and of schreibersite, which on the contrary is present in large amounts. Sometimes it 

 is composed of true nodules measuring possibly 1 cm. in diameter, sometimes it forms a kind of coating around the 

 peridote or around the small masses of sulphide. It is of a tin-white color, slightly yellowish, very fragile, insoluble in 

 chlorhydric acid, and very strongly magnetic. 



The silicate portion of the Kiowa meteorite is formed entirely of olivine, which affords the closest analogy with 

 that of Pallas. It does not form true crystals in any part, but cleavage fragments much rounded and covered with 

 metal. 



In thin sections, under the microscope, this peridote presents numerous cleavages, many of which are as it were 

 injected with matter entirely opaque, which pass insensibly into zones with which the mineral is traversed. These 

 latter frequently contain opaque inclusions, where may be seen, under strong magnifying power, the outlines of 

 octahedral forms. Huntington found chrome iron, but the most searching study fails to show any magnetite. The 

 yellowish zones and the inclusions they contain proceed without doubt from a peculiar alteration of olivine. There 

 may be found near them portions limited by the cleavage and which are evidently serpentinous. 



Some specimens of this meteorite are very exceptional in character. With the usual structure and. cohesion, they 

 show forms of blackish and opaque mineral grains cemented together by a network of oxidized iron. A glance suffices to 

 show that they result from an alteration of normal specimens. The metallic skeleton has been oxidized and the peri- 

 dotes radically changed. Analysis shows the ferruginous oxide to be magnetite. This constitutes almost the entire 

 network between the silicates and the loose filaments in the fissures of the peridotes. I reproduced by heating to redness 

 in the vapor of water a fragment of the Kiowa meteorite, with all its characteristics. 



Strictly speaking, one would suppose that the heating necessary to generate magnetite would date from the passage 

 of the cosmical mass through our atmosphere, but it is clear that the vapor of water would not, at this moment, intervene 

 in sufficient quantity. It is therefore necessary to conclude that the oxidation took place in the meteoric medium 

 itself, where jets of vapor analogous to our terrestrial steam volcanoes act upon the metallic rock previously constituted 

 and heated to redness. 



In the Paris catalogue a further description 7 is given which in part repeats the previous 

 observations and in part adds to them. It is as follows: 



The Paris museum contains, besides other specimens, a fine polished sample of more than 1 kg. weight of the 

 Kiowa meteorite. 



716°— 15 6 



