182 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



A careful study of the meteorite was made by Wadsworth ,2 as follows : 



This is a peridotite consisting of a grayish granular groundmass, holding irregular grains of olivine and diallage. 

 The olivine grains are of various sizes from very minute ones to those of two inches in diameter. Scattered through the 

 mass in irregular nodular jagged forms, occurs iron. Some bluish-gray fragments were seen inclosed but of an unknown 

 nature, although they may be olivine. The groundmass is identical in appearance with that of the finer grained peri- 

 dotites and, excepting the iron, the rock is strikingly similar to some from North Carolina. 



Two or three patches composed of yellowish-green olivine and a glassy white mineral were seen. The latter resem- 

 bles feldspar or quartz, but it would probably not be found in the section or by chemical analysis unless especial por- 

 tions were taken for examination. The iron shows imperfect dodecahedral forms with striated faces. One imperfect 

 form resembled a cube face modified by two pentagonal dodecahedral planes. A few small black grains were seen 

 resembling picotite or chromite. The crust in some places shows that it was derived from the fused olivine; hence if 

 the fusion point of this olivine could be ascertained it would give the minimum temperature of the surface during its 

 passage through the air. The specimen above described, in the Harvard College cabinet, is said to weigh 28 pounds, 

 and it affords, on account of the large extent of its fractured surface, a good opportunity -to study the microscopic 

 characteristics of this peridotite. This specimen in some places shows the remains of an internal cavernous structure, 

 its cell walls being lined with minute crystals. 



Section: A grayish groundmass, holding grains of enstatite, olivine, and diallage, with iron and pyrrhotite. The 

 groundmass is composed of a crystalline granular aggregate of these minerals. 



The olivine is in clear rounded grains of irregular outline. Lying in the olivine are numerous grains and irregular 

 masses of iron which are usually confined to certain portions of the mineral and are wanting in some crystals. Besides 

 the larger, easily recognizable, irregular, semispongelike masses of iron, surrounding, projecting into, or included in 

 the olivine, droplike forms are seen extending in irregular lines from points on the larger iron' masses through silicate. 

 These globules are of every size, from those whose metallic luster and character can be readily recognized with low 

 powers to those remaining a fine dust when magnified a thousand diameters. It can not be said that the finer, dustlike 

 portions, resembling the globules in the basaltic base, are the same as the larger globules of iron; but the gradual tran- 

 sition in size between the grains of different sizes, and, with the increase of power, the increase in number of globules 

 that can be recognized as metallic iron leads one to suspect that all these granules, whatever may be their size, are of 

 the same origin and material — iron. These forms, in the minute state, are similar to those of the inclusions in the olivine 

 of the Cumberland pallasite, but in the latter case the iron, if occurring, would be oxidized. Some of the olivine grains 

 show a fine cleavage adjacent to the cross fissures. 



The enstatite is in irregular and oval masses, with a perfect longitudinal cleavage and a cross fracture. The 

 extinction takes place in polarized light parallel to the cleavage. The enstatite contains inclusions of olivine and of 

 iron, the same as previously described in the olivine. 



The diallage has an irregular longitudinal cleavage, its forms being the same as those of the enstatite. The cleavage 

 lines of the diallage are either cut by irregular cross fractures, or connect by oblique fissures, so as to give an irregular 

 net work over the face, rendering it more obscure and cloudy. The extinction is oblique to the principal cleavage planes. 

 It contains the same inclusions as the enstatite. While the olivine, enstatite, and diallage are all clear, transparent, 

 and colorless in the thin section, yet their cleavage characters are so distinct that in general they can readily be dis- 

 tinguished from one another without the use of polarized light. 



The iron and pyrrhotite are in detached granules, droplets, irregular jagged masses, and in imperfect spongelike 

 forms. In some cases they form an irregular network in the groimdmass, and in an imperfect ring surround the larger 

 grains of olivine, enstatite, and diallage. The material for the above-described sections was purchased from W. J. 

 Knowlton of Boston. 



A figure represents a central crystal of diallage with the surrounding mass of olivine, enstatite, diallage, iron, 

 pyrrhotite, and the ferruginous staining. 



Another figure shows the semispongelike mass of iron and pyrrhotite with their inclosed silicates, forming a ground- 

 mass holding two porphyritic crystals of diallage and enstatite, showing their characteristic cleavages and inclusions, 

 although the latter are imperfectly represented. 



Doctor Smith's chemical analysis was made in such a manner that it is impossible from it to draw any conclusion 

 as to the relative proportion of the elements in the mass as a whole. 



I can find no evidence in the sections that its materials ever held any other relation than the present one, and no 

 sign of a former fTagmental state; but I do see evidence that is convincing tome that the entire mass has been 

 formed by contemporaneous crystallization, i. e., it has the same structure that a terrestrial lava of the same composi- 

 tion, cooling under conditions that would allow the entire mass to crystalize, would have. The inclusion of the iron 

 in the silicates, indicating their later solidification, would show that the iron was not a posterior emanation. Such a 

 formation as Meunier supposes could not take place without leaving a record behind of its action. 



The sections obtained from Prof. C. W. Hall, of the University of Minnesota, who was expected to publish a com- 

 plete microscopic description, are, in their general and mineralogical characters, so unlike those already described, that, 

 were it not for the source from which they were obtained, it would be very difficult to believe that they came from the 

 same meteorite. 



They have a confused light-greenish-yellow groundmass, holding irregular masses of olivine, enstatite, and feldspar. 

 The gToundmass appears to be composed of olivine, enstatite, feldspar, pyrrhotite, and magnetite. But little native 



