368 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 58. 



(pi. 23). These often show the broad twin laminae characteristic 

 of anorthite — ^with which species they seem to agree optically — and 

 are readily soluble in hydrochloric acid. This at times is strongly 

 suggestive of the well-known maskelynite type, into which it, indeed, 

 seems to grade and of which I am at times inclined to regard it as an 

 unusual phase. The second occurs in the usual lath-shaped forms 

 characteristic of basic eruptives, and is unquestionably the result 

 of crystallization in place if not a direct secretion from a molten 

 magma. It is to the larger forms that attention needs particularly 

 to be called. Their most striking features are the irregular outlines 

 referred to above. These, as will be noted by reference to the fig- 

 ures, extend outward into all the minute interstices of the other 

 silicates, often in such minute ramifications as to show that they 

 were the last constituent to solidify from a very liquid magma. 



In numerous instances the interior of a crystal is clouded b}- inclo- 

 sures and bubbles. Figure 3 shows a marked example of this. In 

 such cases extinction is simultaneous and uniform for the most 

 part over border and nucleal portion alike. In Figure 3, on Plate 23, 

 especially referred to, the colorless border, it will be noted, includes 

 small crystals of pjToxene and perhaps olivine, their small size pre- 

 venting an exact determination, as their optical properties are ob- 

 scured by their host. The first thought that arises on seeing these 

 peculiar forms is that of secondary enlargement. But for the fact 

 that the olivine and pyroxene both fuse at a somewhat lower tem- 

 perature than the feldspars, one might consider these borders as 

 products of a metamorphism due to a rise in temperature, a view 

 sometimes held regarding the maskelynite in chondritic stones. 

 Attention should also be called to the elongated bubbles or cavities 

 extending from nucleal portions out into the clear border in the 

 upper left as the figure is oriented in the plate. In a few instances 

 inclosures in the border were noted, which it was thought from their 

 lack of color, form and occasionally characteristic fracture may be 

 apatite. Here again optical properties are obscured by the host. 



The facts presented above, together with the general linear ar- 

 rangement of the cavities and their secondary minerals, and the pecu- 

 liar slag-like condition of the mass as a whole, lead me to consider 

 the EsthervOle meteorite as a product of metamorphism — a stone 

 originally consisting of fragments of the various silicates noted 

 which has been subjected to such compression, heating, and reducing 

 vapors as to render the more finely disintegrated material holocrys- 

 talline. Incidentally it has become impregnated with metal result- 

 ing from the reduction of some preexisting ferrous mineral. That 

 this may have been a chloride (lawrencite) is possible, but if so the 

 mass has suffered shrinkage, since this mineral would yield, theo- 

 retically, but 44.1 per cent of metal. The peculiar sponge-like 



