366 Br. Walter Flight — History of Meteorites. 



1812, August 5th. — Chantonnay, Dep. de la Vendee, France. 1 



In the winter of 1874 Tschermak published a paper on the structure 

 of the meteorites of Orvinio (see page 222) and Chantonnay, which 

 appear to have many characters in common. Sections of the latter 

 stone, three drawings of which are given in his paper, show it to be 

 made up of chondritic fragments, covered with a dark-coloured crust, 

 and cemented together with a black and in places semi-vitreous 

 material. The fragments are not very abundantly provided with 

 spherules, although large ones are here and there met with. It 

 differs from the chrondrite of the Orvinio meteorite in containing less 

 iron ; a section shows olivine, bronzite, a finely fibrous translucent 

 mineral, as well as nickel-iron and magnetic pyrites ; the presence 

 of chromite was not recognized. Fine black veins of a mineral 

 traverse the fragments here and there, and are connected with the 

 cementing material. Similar veins are noticed in the meteorites of 

 Lissa, Kakowa, Chateau Renard, Alessandria, and Pultusk ; and in 

 the Lissa and Kakowa stones they present the appearance as if the 

 meteorite had originally come in contact with a molten material 

 which had been injected into the clefts of its surface. Eeichenbach 

 was of opinion that the black veins were directly and intimately con- 

 nected with the fused surface ; his view, however, is open to 

 question, from the fact that the interior of a meteorite has usually a 

 low temperature when it reaches the earth's surface. Moreover, in 

 the case of the Chantonnay stone, clefts are to be met with into 

 which the black matter of the crust has penetrated to a depth of 6 

 mm. only, although the cleft remains partly open. The black semi- 

 vitreous magma consists of an entirely opaque mass, enclosing flakes 

 of the silicate, which forms the fragments, as well as occasional 

 spherules. 



Although Eammelsberg, who analysed this stone, does not describe 

 the physical characters of the material he operated on, and did not 

 separately examine the fragments and the cementing material, as 

 Tschermak has done in his examination of the Orvinio meteorite, to 

 find that the two constituents have much the same composition, 

 Tschermak points out that the two meteorites have a very similar 

 constitution, differing mainly in the proportion of iron. The 

 characters observed in these two meteorites point to the conclusion 

 that they did not originally possess their present constitution, but 

 that to the disintegration of a solid rock-mass and its subsequent 

 cementation with a semi- vitreous magma their present appearance 

 is due. Although they resemble somewhat the eruptive breccias, 

 they differ from them in that the meteoric cementing material is less 

 homogeneous, and encloses fine flakes of the rock itself. The Chan- 

 tonnay stone exhibits the fine texture observed in some metamorphosed 

 breccias. The two stones convey to us evidence of changes which 

 must have occurred on the solid surface of some planet that was 

 subsequently reduced to fragments. 



1 GL Tschermak. Sitzber. Ah. Wiss. Wien, lsx. November Heft, 1874. 



