252 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



what is left of the crust. Small, rough, wart-like processes are seen generally over the surface, some due apparently 

 to the projection of chondrules through weathering, while others are the less altered fragments of crust. 



Parts of the meteorite, especially near the point of impact, and the fragment (0.75 pound) which shows no fresh 

 fracture surfaces, are covered with a fine, yellowish white powdery substance, which effervesces but slightly in acid, 

 and is apparently a light clayish soil. The same substance is found in the cracks previously mentioned. 



The fresh fracture is uneven, and the stone, as thus seen, is fine-grained and compact. The general color is dark 

 rusty brown, which under the lens is seen to be a mottled brown and black. Small, glistening streaks of nickel iron 

 are scattered through it, but no troilite was seen. The lens also reveals translucent grains of olivine and bronzite. 

 Small rounded chondrules are also seen here and there, but are not very numerous. 



It is very evident that the oxidation of the iron from weathering extends far into the mass, though possibly a sec- 

 tion through its center might reveal fresh substance. Of the stones in the Yale collection it resembles most that from 

 Salt Lake City, and is also much like the decomposed portions of the Bluff, Fayette County, Texas, meteorite. 



Under the microscope the stone is seen to be composed of quite numerous chondrules of bronzite and olivine, with 

 fragmental crystals of olivine, bronzite, and a little pyroxene, in a rather brecciated groundmass of the same minerals, 

 together with some interstitial matter, which seems to be glass. Nickel iron is present in the form of small, angular, 

 irregular masses. Patches and veins of dark, reddish-brown, and yellow ferruginous substance are present, and show 

 that considerable atmospheric decomposition has taken place. A few small fragments of plagioclase are also to be 

 seen, but no troilite, and nothing which could be referred with certainty to maskelynite. 



On the whole, I am inclined to class this stone with Brezina's group 37, " krystalliniseh Chondrit, breccieniihnlich 

 (ckb)," though I have no sections of either of his two examples for comparison. It will be remembered that it resem- 

 bles megascopically the less fresh parts of one of these, the Bluff meteorite. 



The chondrules of bronzite run up to nearly 2 mm. in diameter, and show, in most cases, circular sections, or 

 nearly so, though angular and fragmental forms are seen. They present the usual fibrous, eccentrically radiated 

 structure. 



The olivine chondrules are somewhat larger, up to 3 mm., and show greater variety. Many are monosomatic, 

 with parallel plate structure and border as figured by Tschermak. The interstitial matter here is granular, colorless, 

 and isotropic, containing small, black, opaque particles. It is possibly a glass, as in the cases described by Tscher- 

 mak, though its pronounced granular character is against this view, and points rather to the idea that it is maskely- 

 nite. These chondrules are usually small and round. 



Porphyritic olivine chondrules are more numerous, as well as the largest in size, and are occasionally rounded, 

 but usually irregular in outline. They consist of oblong grains and crystals (showing traces of pinacoids and domes) 

 of colorless olivine, lying pell-mell in a gray or colorless, finely fibrous groundmass. This is formed of patches of 

 straight, narrow fibers parallel over small areas, each small area extinguishing as a unit, but unlike those adjacent, 

 where the fibers run in another direction. It was supposed at first that these thin, colorless rods were a rather basic 

 plagioclase, since they extinguish at various angles up to 20° with their long axes, and their polarization colors are 

 grays and pale yellows. Close examination under high powers, however, revealed the fact that in many places there is 

 no break in continuity between the fibers and distinct adjacent olivine crystals, and that in these cases both crystal and 

 fibers extinguish simultaneously. They must, therefore, be referred to olivine, and the apparent oblique extinction is 

 due to the fact that the fibers project obliquely from the surface of the olivine crystal, seemingly in the direction of a 

 domal or prismatic plane. That they are rods and not plates (as in the preceding type of chondrules) is shown by 

 their sections in certain places, where they present the appearance of small rounded grains. Such skeletal develop- 

 ment is a not uncommon feature of olivine, as is well known. 



Other porphyritic chondrules are seen in which olivine crystals and fragments are embedded in a fine-grained 

 mosaic of olivine and enstatite grains. One peculiar ovoidal chondrule was observed, composed of a long, seemingly 

 corroded, olivine crystal, surrounded by a mosaic of small grains of the same mineral. There were a few monosomatic 

 chondrules of olivine, with approximately circular outline, but curiously and irregularly hollow, the interstices be- 

 tween the separate patches of olivine being filled with granular bronzite. Others again were found with monoso- 

 matic borders and portions of the interior of bronzite, containing olivine grains. 



The crystals and fragments of bronzite and olivine offer no features of special interest. They are colorless, except 

 where stained by ferruginous decomposition products, and are quite fresh, even the olivine showing no traces of ser- 

 pentinization. Each mutually incloses the other, so that they were apparently crystallized at the same period. Both 

 include small angular fragments of iron. Only a few crystals and fragments which could be definitely referred to 

 pyroxene were observed. In one case two pyroxene fragments, giving oblique extinction, are inclosed in a patch of 

 bronzite. A few grains which may be referred to plagioclase were found, one of these showing traces of twinning 

 lamellae. 



Grains of nickel iron are quite abundant. They are all small and angular and irregular in outline, and appar- 

 ently generally later than either the olivine or bronzite, as they are xenomorphic toward these and occupy the inter- 

 stices between them, and also include crystals and fragments of these minerals. At the same time, as we have seen, 

 small particles of iron are included in these minerals. 



The iron has suffered greatly from oxidation, being usually surrounded by yellow, or deep reddish-brown, trans- 

 lucent, doubly refracting matter. This is probably linionite, since it answers to Pelikan's description of limonite 

 under the microscope, and since the analysis shows that there is no silica, above that necessary for the olivine, etc., 

 to form a ferrous silicate, as it was suggested to be by Kunz and Weinschenk in the case of the Washington, Kansas, 



